Start Up GW, Hard Lock in 20s?

Ok, I've seen this posted in a few spots, but my problem is kinda weird.

I have these specs:

Athlon 64 3000+
2GB crucial
GEForce FX 5700 Ultra

And what happens is, the moment I login on a character, the mouse pointer (optical MX700 mouse - Logitech) starts behaving erratically, jumping all over the screen, although its following the movements I'm making.

If I run GW in windowed mode and switch to another prog like IE or iTunes, the mouse still behaves erratically, but I have no slowdown on my keyboard input for example.

If I run GW fullscreen or on windowed mode for an extended period of time without switching to another program, the machine hard locks and I have to reset. I thought perhaps the machine was overheating, but my CPU temp never exceeds 45c, and while high, it doesn't cause shutdowns for any other program.

Anyone have any ideas?

Just because your CPU is fine doesn't mean nothing else can be overheating. I'm not really sure, but it seems that because not only does your mouse act funny, your PC also hard-reboots it's something else. Do you play any other games (modern ones -- CS and the like wouldn't count, it doesn't stress the system much). Could be a GW problem, but if it's something with your PC, it's something rather basic - i.e. PSU/Mobo. Try checking the temperatures for your PSU and Mobo right after it reboots (check it through BIOS. BIOS gets the temperature readings from diodes at the exact location of the heat being given off - for example, if your BIOS says your CPU temp is 118 and a windows-based program says it's 114, the BIOS is correct. Programs don't use these same diodes (or don't have access)).