PC Restarting all the time

[ToAsTeD]

one of the guys suggested checking system events - did that - and there was nothing there.
I thought that there might be dust in the fan - checked that - opened and cleaned it - still no impact.
Replaced the cpu fan and heatsink - and the problem still happens.

one thing i noticed though is that it happens when i am running something that may require additional power -
- when i insert a cd/dvd into the drive - within 2 seconds of that - it restarts itself
- when i watch a video on the pc - also restarts itself
could it not mean my power supply is packing up?

the machine is not on a lan.
will try the lithium battery option - have already backed up the pc - so last resort is a clean start.

By the sounds of it, every time it requires a little more juice it restarts. Replace Power supply unit with a decent make and wattage.

 

[unwired]

By the sounds of it, every time it requires a little more juice it restarts. Replace Power supply unit with a decent make and wattage.

yeah, that was the cause. Also replaced the CPU fan and heatsink for good measure.
Previous power supply was 250w. And all I have is a P4 3.0Ghz.

Reinstalled windows again and the machine is moving like a bomb.

Thanks guys for all the tips