Windows XP My Computer not responding

Clarifications

Then click on 'OPEN' at the top of the dialog menu?

Does it open from here?

Things like the CPU usage and Page File Usage are the Important things.

Is this computer part of a Domain and if it is could there be something like a GP involved preventing My Computer from being opened?

Has this system been scanned and certified free of Infections with things like the Installed and up to Date AV Product that is on this computer and then Malware products like Spybot S&D and Malware Bytes?

Spybot S&D

http://www.safer-networking.org/en/download/index.html

Malware Bytes

http://download.cnet.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html?tag=mncol&cdlPid=11015805

What else if anything is this computer not doing?

Col

I have had the same problem several times. In my case it has always been related to a network drive that I had mapped and that drive was no longer accessible for some reason. Try disconnecting a mapped network drive and see if that helps.