Computer lock-ups

All right. So I have this computer that randomly locks up! At first I thought that maybe it was a virus or something… It wasnt. After running AVG, Nortans, and a few online virus scanners came up clean I ruled it out… So, my next step was to start removing piece by piece…. So I did. It had little to no effect. My next thought was maybe it was heat realted.. So, I downloaded a MotherBoard Moniter, which takes a reading of the current temps, which were as difined by AMD's website, just fine. But I went ahead and bought heatsink/fan anyway. It didnt help.. I also thought maybe it had something to do with the power supply. But, I couldnt think of any way to test such a thing without finding another computer, so I went to Circut City and bought a new one. Went in like a dream, but still had the same ol' problems. Also, I ran serveal hard disk scanning utilitlys to check the status of the drives, which all came back as "Healthy"… My next step was the video card. I deleted the current drivers and downloaded the newest. I did nothing. So then I went back to the windows drivers, did nothing to help… So, I bought a new card… Didnt help.. Naturally, I thought maybe the RAM… All the testers that I used came up as healthy… I now seem to be out of options… It just freezes. No error messages, just nothing… Also, it freezes at random times. It doesnt matter whats being done, just frozen…. Meaning, it doenst matter if its just sitting there not being used, or if its just surfing the net, or if I'm playing a game.. Today I got on at around 3 PM, and it was frozen, and the clock read 9 AM.

How many icons are in your system tray?

14 and then a modifed version of windows clock. Then just on the desktop, thers a Desktop Calender, a watch, some weather moniter thingy, oil price moniter, and a weather.com backround that updates the current weather map.