Computer won't start

[winuxapple]

I have this problem, my sister always play Sims 2 then when she plays for a long time,the my DTS crt monitor become blurred and my speaker's sound become distorted.This happened two times only because of that game.But i post this on hardware because,the first time it happen, we just shutdown the pc and it start normally.The secon time,it wont start, the monitor just said "Signal Cable Disconnected", I reboot and the same happend. I've wait for a long time and open it again, the same happen, but my HD is lit,even the DVD drive and fan.So we plugged and unlugged all the sockets in the CPU's back and its plug from the Voltage Regulator.The VOILA! the CPU starts.But now, its the 3rd time, because of that game again.I did everything i did the last time for how many times but it didnt relly start.What should I do.This is my main PC Spec:
WinXP
512mb of RAM
80GB of HD(12GB is left)
Intel Dual Core 1.6 GHz
Thanks i adVANCE..

[patio]

With 12G left free you are just about at the Windows threshold for normal operations.
You will start to see performance drop off at this point.
Time to do some housekeeping and burn some stuff to CD/DVD and free up some additional space.
Run defrag when done.