Computer won't start up

[anthonyvop]

On occaision my PC would freeze up and I would have to hard shut off.
Some times after freezing my computer wouldn't start back up.

When i turn it on the monitor goes on and I hear the fan running but nothing else happens.
Previously i have run anti-virus software and Highjack this with no issues.

Any Idea what it could be?

[Broni]

Windows version, computer specs: processor speed, amount of RAM, hard drive size/free space.
Who checked HijackThis log?

[anthonyvop]

Windows XP Home

AThlon 64
2.0 Ghz
2000 MHZ fsp
512 KB  L2 Cache

160 GB ATA harddrive

Memory
512 MB DDR  SDRAM dual Channel

I had a friend who works for a PC company check the log when I first started having problems.
Now I can't get the logs.

I have discountected various hardware one at a time and that doesn't seem to be the problem.

[Broni]

Will it shut down from Safe Mode?

[anthonyvop]

Will it shut down from Safe Mode?

I can't get it to start up to be able to shut down in safe mode.

[anthonyvop]

Anybody?