First of all, voltage fluctutation is a general problem where i'm living, but it doesn'T effect my PC about five years till yesterday - if it caused this.
during boot section, i heard not ordinary "slapp"(like something has burnt) sound from case, later computer shutdown itself. then i tried to turn it on again but it seemed not pass POST, no usual "beep" sound here.
opened case, nothing seemed to be burn. i tried remove each one of two RAMs, remove BIOS battery for 20 seconds to reset it, didnt work.
later i realized processor fan got loose, i replug it and computer passed POST, everything seemed to be OK but, here are the problem, my computer freezed, i reboot it many times, and it always totally freezed after nearly 10 minutes, no keyboard combination worked either. no beep sound during freezing but one time(not always), scroll and caps locks are blinked, and i have no wireless(i'm using kubuntu).
suspected heat, and plugged off processor fan and cleaned it, but it didn't worked.
so what'S the problem? suspected cannot plug the proc&fans correctly but if it was in this way, pc never pass the POST, or it can be?
or processor had a total problem? may it burned partially?
i have an intel p4 3.0 ghz ht proc and albatron px484pv mainboard.
P4's had a thermal cut-out so in theory they shouldn't burn out. But that also depended on the motherboard to support it. In all likelihood your system's knackered (possibly even mobo + RAM + CPU). The fan once failed on an old AMD system of mine while the CPU was maxed out (left over a weekend). that really killed all three main components.
Also, if you heard an odd loud noise, check the Capacitors (small/large cylindrical components) on the motherboard. Check that none have failed by looking or swollen/cracked end caps or even ones where entire casing has blown off (voice of experience ;-) ).