Crazy computer

[vinrex7]

Recently my pc has gone crazy. sometimes for no reason it just freezes, and i cant do anything, and the cpu is 100% flatout. this happens if i'm not even using it sometimes. i'm using norton anti virus and firewall. i have done virus scans and all seems ok. anyone got any ideas?

[Kerplunk]

Which process is using the CPU? Goto task manager and find out.

[obione]

hi
this may sound daft but how long is it since your pc was dusted inside the tower.
i was having this problem and worse even had the blue screen of death a few times, but could not work out what was wrong, then as a last resort looked in the case and boy was it dusty, so after unplugging i carefully hoovered out the inside and also took off the fan (remember which side is up) on the heatsink and hoovered all dust collected on there too.

dont seem to be having same problem anymore so am assuming the processor must have been overheating and causing problem. hope this helps

[Kerplunk]

I disagree if as vinrex7 says the cpu is 100% flatout then this cannot be caused by overheating. A program must be using all the available cpu power.