[V3515] switches off at random

[cmb1960]

My V3515 runs XP and may work for hours or shut off uexpectedly at any time. The problem seems to be replicated if I tap the case to the right of the touchpad or plug in a usb device. Sometimes get a blue screen (different error each time) and sometimes not. POST sometimes works ok, other times it takes several goes. Have unplugged and reasetaed memory, hard drive and wireless card but no different. Seems likely to be a motherboard problem to me but I wondered if anyone else had solved a similar problem? It's out of warranty so really want some help to fix it at a realistic price!

ps Have also renewed thermal paste and cleaned fans etc so fairly sure it's not overheating - shut downs not related to high or low use either

[ASBO]

I also have the same problem but it happens when i'm playing a video game ( warhammer dark crusade ) , it may happens from the overheating , my laptop is going to melt , so what is the solution