Computer freezes

[#1]

After two visits from Dell man and replacing the
the motherboard on both occassions,and also replacing the battery my pc still freezes after a while they told me I might ba a virus and they will clean my hard disc or run a anti virus check.

[#2]

There is a type of freezing where the freeze is not instantaneous, you can still move the mouse cursor around for a while and click things but nothing responds.  Eventually even the cursor will no longer move and the computer is completely frozen.  That type of freeze is very often caused by a faulty hard drive; I have seen it several times and I can recognise the symptoms.  The computer tries to read/write from/to a bad area of the hard drive but the process proceeds at an infinitesimal rate.  Everything gets queued-up waiting for this read/write to finish but the computer hasn't the good sense to give up.  Because only certain areas of the hard drive are affected it may be some time before one of these bad areas is encountered.
A fairly good diagnostic is to run the full five-stage chkdsk.  You will find that this probably gets stuck and never completes; or at least takes many many hours.
Insist that Dell replace the hard drive with a new one.        

[#3]

Thanks for your reply my computer was freezing on and off the last few days I ran CC Ceaner through the registry yesterday and since then I have had no problems.The Dell man is coming on Monday to wipe the hard disc he  thinks that I might have a virus and by cleaning the hard disc it may solve the problem,if I have no more trouble tomorrow I might tell the technician to leave well alone time will tell.

[#4]

I really think you should try to run chkdsk before the Dell man comes.  Follow the instructions here http://www.w7forums.com/use-chkdsk-check-disk-t448.html but if you use the first method make sure you also tick the box that says "Scan for and attempt recovery of bad sectors".

[#5]

I would absolutely agree, you need to know the hdd is ok. No point doing a reinstall on a drive thats starting to give up. Instead of the windows tools you could also use one of the manufacturers tools. I use seagates seatools, as it can also run in its own environment, bypassing windows completely.

[#6]

I have become suspicious of disk manufacturers tools since seeing one "pass" a disk that was pretty obviously faulty.  After all, disk manufacturers have a vested interest in taking an optimistic view about the state of a disk.  But I'm grateful for Penfold's support.  In my experience a faulty hard disk is a common cause of a computer freezing (something that has arisen in the last few years) but Dell seem to have a blind spot about this possibility.   

[#7]

I only ever use the seagate one, never cared much for the other manufacturers tools.  I must admit however, the tools built into Win7 are much better than XPs (never had the privilidge of using vista )

[#8]

Quote from: penfold

I only ever use the seagate one,

I've always found Seagate Tools to be the easiest to use and the most comprehensive. They've always been spot on for me.

[#9]

The freezing saga as stopped this weekend was trouble free I did run a registry scan when I was having problems and I cleared out some issues with CC Cleaner I would like to think that it was a registry  problem but i have had no trouble since. I did a chkdsk scan  which took some time and added scan and attempt I am not sure if that shows up any results because it did not appear of any problems.The man from Dell came today ready to change the disk but as thing s are running well he left well alone he did do some diagnostic tests and he as left the parts with me in case of any problems,so far the last  three days have been fine.

[#10]

Freezing (keyboard and mouse lockup) is normally attributed to a hardware fault.  If it were me I would run the manufacturer's test on the hard drive first and then run memtest86 to check the system ram.  I do this to systems every day at work and you would be suprised the amount of brand new or nearly new laptops I have looked at with failing harddrives.  Sometimes they are faulty out of the box!
Its very rare to get software problems causing a full system lockup.  Really the dell tech should have tested both before the mainboard was replaced.  Faulty CPU can also causing freezing.  Prime95 is good for checking system reliability, it loads the cpu 100% and can also stress the ram in the windows environment. 
I have had wireless cards being at fault causing full system hang aswell.  Easy way I diagnose that is disable the wlan and run it on ethernet, if it still locks up its not the wlan.