Network/Internet Problem

[#1]

This is an odd one.
The XP computer wouldn't see the network or the router hence no Internet.
Checking router shows it wasn't connected even though the green light for the LAN connection was lit.
Checking network adapter status showed no problems
Kaspersky reported that the network wasn't present even though Windows didn't flag up a problem.
Rebooting the PC didn't fix it
Rebooting the router didn't fix it but a PC reboot after the router reboot fixed it.
Obviously there are a number of possibilities
Router problem
Network adapter (integral with the motherboard) problem
Cable between PC and Router fault
XP playing silly beggars
Any thoughts for diagnosis if it happens again

[#2]

Maybe a simple click on the "Repair" button might fix it!

[#3]

get a decent operating system?
/coat

[#4]

I have seen this behavior on at least 7 or 8 XP machines, more often wireless but sometimes wired too !
I have 'solved' this behavior by NOT allowing XP to use DHCP to establish it's network address or DNS values.
Once the XP network properties are changed to all static IP addresses this NEVER reappears.
I know on my network that this issue isn't caused by the router as I have various OSes, and it only the XP machines that show these symptoms.
Interestingly as you discovered rebooting the router and then the XP machine clears the problem (for a while - I reckon a few weeks), but when this deadlock has occurred I find that another OS (in my case usually Ubuntu) can still do DHCP setups when the affected XP machine can't.
I know this doesn't explain why, but static IPs fixed it for me !

[#5]

the wifes XP netbook often does that and we have to hit the WiFi repair button  (right click on the WiFi icon and repair), never get it on my Win 7

[#6]

As this is the first time this has happened I will see if it happens again.
As I said XP thought the network was fine but I will try the repair option if it ever happens again before going for fixed network addresses

[#7]

I just found this solution that may (or may not) help someone.

[#8]

Thanks - I have copied the solution to a txt file on my desktop to find it later if needed

[#9]

If you have and old style PC desktop/floor standing with a separate network card, sometimes reseating the network card will help if it has a PCI interface.
Note down the IP configuration from the properties screen.
Switch of the PC and remove the power cord. Open the casing and find the network card. release the locking screw and physically remove the card. Reverse the process and reboot the PC. On rebooting the XP will automatically reinstall the drivers for the network card. You may need to reconfigure the IP settings too.