PC intermittent freezing/Start-up failures

[#1]

Hi guys,
Ok, I can build a PC but my hardware diagnosis has never been the best (pretty much a case of trial and error).
I posted something similar to a few forums the other day and whilst I seem to have been OK for the last 48 hours or so, I thought I'd post here to gather peoples' thoughts...
I've recently starting encountering problems with my PC intermittently locking up. When it does this the whole thing completely freezes. Ctrl, Alt + Del fails to respond and the machine needs to be rebooted using the reset/power switch. There's no error and the screen is simply frozen at whatever it was doing at the time the error occurred.
This seems to be happening around once a day (I've been finding it in this state after waking up in the morning).
I'm running Vista Ultimate, ASUS P5P mobo, Q6600 2.4Ghz processor, 4GB of DDR2 RAM and a GeForce 8800GTX. I've an internal IDE drive (connected via a SATA converter with my Windows install on), another internal SATA drive and an external USB drive.
I'm wondering where's best to start with diagnosis of this problem. The event viewer gives me no clues as there's no event logged at the time the problem occurs, simply an error notification the next time the machine's booted saying it didn't shutdown properly last time. This is what leads me to believe it's a hardware issue.
It may also be worth me noting that on occasion during the boot process, the machine hangs on the Asus flash screen (where it tells me to press Delete to get into the BIOS etc.) Hitting the reset switch normally fixes this. It sometimes happens if my iPod is docked to my machine in which case removing it and then restarting seems to fix it.
Would be grateful for any suggestions on where to start as this isn't my forté

[#2]

Could be a RAM problem:
1) Run memtest86+ and leave it running through several passes. Given the amount of ram you have this could take a long time.
2) Are all the ram sticks the same rating / speed?
3) Try with only 2GB of Ram and see if the same problem occurs. Or even try with one stick at a time (if you are using 1GB sticks).
4) Does the mobo require matching pairs of ram (sometimes indicated by having 4 ram slots in 2 colours) and if so are the pairs the same rating / speed. If not try altering the order to see if it improves.
Or PSU...
5) Are you sure your PSU is up to the job? What make and rating is it and do you plug the graphics card into it (i.e. Does it use a Molex connector or take its power from the mobo slot)
Or heat...
6) Check case and CPU fans are working and things are not getting too hot. Asus normally have sensor software on the install / driver CD to show system temps etc although they may not work with Vista yet.
It could also be (spit!) Vista!!! You are on your own if it is!!!
Some Mobo's have a BIOS recovery mode where default setting are written to the BIOS after system crashes / lock-ups. Its normally a safety mechanism during overclocking to allow the system to boot again with default settings after you overclock too much. The BIOS may think the lockups are due to overclocking so hangs on the BIOS startup so you see it has reset to defaults.

[#3]

Thanks Peter,

Quote from: Peter

Could be a RAM problem: 1) Run memtest86+ and leave it running through several passes. Given the amount of ram you have this could take a long time.

Yeah, I've already downloaded memtest86 to check this but am yet to run it (shall try overnight tonight).

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2) Are all the ram sticks the same rating / speed?

Yes, they're identical.

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3) Try with only 2GB of Ram and see if the same problem occurs. Or even try with one stick at a time (if you are using 1GB sticks).

I'll see what the memtest comes back with first.

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4) Does the mobo require matching pairs of ram (sometimes indicated by having 4 ram slots in 2 colours) and if so are the pairs the same rating / speed. If not try altering the order to see if it improves.

Yes, but as mentioned all RAM is the same.

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Or PSU... 5) Are you sure your PSU is up to the job?

I hope so. 650W should do the trick. It's one of these and yes the GFX card is plugged into it.

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Or heat... 6) Check case and CPU fans are working and things are not getting too hot. Asus normally have sensor software on the install / driver CD to show system temps etc although they may not work with Vista yet.

All fans are operable. The processor can run a tad hot at times (50C) but it hasn't been a problem in the past.

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It could also be (spit!) Vista!!! You are on your own if it is!!!

has been fine for the last 3 months.

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Some Mobo's have a BIOS recovery mode where default setting are written to the BIOS after system crashes / lock-ups. Its normally a safety mechanism during overclocking to allow the system to boot again with default settings after you overclock too much. The BIOS may think the lockups are due to overclocking so hangs on the BIOS startup so you see it has reset to defaults.

Yeah, it does have this functionality I think however it shouldn't stay stuck there though should it?

[#4]

Are all the heatsinks clean? It is amazing how much dust can build up on them, and it doesn't take much to significantly reduce the ability to disperse the heat.

[#5]

Unless you are running  64bit vista it cant address 4 gig of ram as it conflicts with the video rams address space.
if you're running a 32-bit operating system, you will only be able to address 32-bits of memory at a time. Multiply that out and you get 4GB, but when you take into consideration the memory reserved for video RAM and bios space, you won't be able to hit all 4GB.
see http://support.microsoft.com/kb/929605
reduce thee ram and try again it may be it has problems with power options if its been idle a long time and its not waking up(bit like me)

[#6]

Yeah, I'm aware of the 32bit Vs. 64 bit thing. My PC actually reports as having 3347Mb RAM in the system properties. Power options shouldn't be an issue as the PC's configured to be running at full power 24/7.

[#7]

Note there are 2 versions of memtest; memtest86 and memtest86+. the + version is the later and better version I find and supports more mobo chipsets.

[#8]

I suspect a voltage problem; what are the voltages (in bios and windows)? It could be that the regulated O/P is just on the border of TTL values and thus outside of their range of operation.
If I were to guess I would say the +5V is the one to watch as this will supply the CPU with power and the one to cause a 'lock-up'.
Good luck.

[#9]

Little did I know but Vista actually comes with a built in memory diagnostic tool. I ran this overnight and it detected no problems (although it does only execute 2 passes).
The original problem hasn't actually repeated itself since this thread was started

[#10]

Ah - there's the problem - insufficient forum contributions always causes freezing....
I had a similar problem a while back. Appears to have been an intermittant problem on my hard drive. chkdsk etc. all said the drive was fine, defragmented etc. - intermittant lockups, particularly at startup time, still happened. Did a backup and restore to a new drive - no problems since then.

[#11]

I had exactly the same problem a while ago too, including the occasional freeze in BIOS.
When I removed  a device from one USB port, and put it in another USB port, everything has been much better since. I therefore put it down to being a faulty USB port.
Also, try cleaning the contacts on your memory sticks and sockets using lint-free paper. Another thing worth trying is simply disconnecting, and then reconnecting, all the cables in your PC.
I also vacuumed out a lot of dust from the inside of my PC, but that's definitely frowned upon.

[#12]

As I mentioned in an earlier post similar to Rob's reply. Some USB externally powered hubs, seem to not like doing everything that's asked of them. For this reason, I ditched the troublesome external hub I was using, and fitted PCI cards instead (same manufacturer Belkin) and have never had a problem with USB since. Hardware (those permanently left in-situ, printers, scanners, Skype etc.)  plugged into the cards were certainly much faster than when in the hub. Could be of course, the external hub was faulty.
PS. you may be better-off blowing dust out, rather than sucking it, try one of those compressed air aerosols used by photographers, usually available in er! photo/camera shops.

[#13]

I was having freezing problems on my Vista box until I discovered that software conflicts were causing it. What AV, Spyware and Firewall software are you using?

[#14]

I did only mean vacuuming the bottom of the PC, not the circuitry itself. I don't want to waste any of my compressed air, but do use lint-free clothes to clean more sensitive things. Static did worry me a bit, but I always make sure my PC is plugged in to a mains socket when I open up the case, and also make sure that I am strapped to the case.

[#15]

Quote from: Bob

It may also be worth me noting that on occasion during the boot process, the machine hangs on the Asus flash screen (where it tells me to press Delete to get into the BIOS etc.) Hitting the reset switch normally fixes this. It sometimes happens if my iPod is docked to my machine in which case removing it and then restarting seems to fix it.

Sounds like a bad IDE controller on the motherboard. Had this before. It's a right pain in the grass as there is no way to fix it other than replace the m/board. This can also affect a running OS as the board can suddenly decide there is nothing connected to that IDE channel and windows doesn't know how to handle the error and then hangs (Just like if you pull out the power supply to one of the HDDs while windows is running).