Sudden mouse/internet/driver/bsod problems

I'm completely baffled. Last night I was using my computer just fine. I went to sleep and woke up hours later to turn on the PC and find my mouse stopped working. I plugged in my pen tablet to use it as a mouse instead, and noticed the tablet driver stopped functioning too (I can still use it as a mouse, but it doesn't work as well without the driver). I then tried to connect to the internet to diagnose the problem, but the net isn't working. I restarted my router and modem, but no progress. The other PCs in my house can connect just fine (I'm typing this from my laptop). I don't remember installing anything new in particular. I ran scans with RegCure, Avast!, and SuperAntiSpyware and removed some random errors but none of the problems I listed seem to be fixed. For some reason I didn't have any system restore points to roll back to. I've tried disabling everything that comes up during startup through msconfig. I've logged into other user accounts and they have the same problems. I'm completely stumped on what could have caused this. I will post a hijackthis log if necessary.

Also, when I ran scans with SuperAntiSpyware after a while I will blue screen with the following error:

PAGE_FAULT_IN_NONPAGED_AREA

STOP: 0x00000050 (0xE3FC8000, 0x00000001, 0x80640199, 0x00000001)

Sometimes it'll mention win32k.sys as well.

I will appreciate it greatly if anyone can help me resolve this.

Check the device manager for device conflicts. You should also check the event log to see if any updates pushed down or system errors.

So I got a copy of hard drive diagnostics, memtest86 and windows XP. I ran the diagnostics, and it passed the short and long tests. I then ran memtest, and there were no problems with the memory either. When I popped in the XP disc, it started reading it but it blue screened even BEFORE the part where it asks you to push ENTER to start XP install or "r" to repair. The error was the same as before, BAD_POOL_CALLER. Maybe the problem is in my other hardware? I was thinking of buying a new hard drive as a LAST RESORT but I don't even know if that will work now.