Sony Vaio laptop shutsoff when processor reaches 100% mayb overheating

[untilted413]

hi guyz

i have a sony vaio laptop nw29gf which came with a genuine win7 home premium 64 bit. the processore intel core 2 duo 2.2ghz and 4gb ram. i have been using it for the last 8 years without any glitch (ofcourse the battery's long gone) but still i never complained until recently

i started a thread here about my dispaly going out and then asking for ur help and then the only option was to reball or re heat the graphics chip which i did and it worked my display is back but the downside was that ever since the reballing i am getting this new problem that my processor usage is getting very close to 100% percent specially when using firefox.
and when ever it reaches 100% or close to it for a few seconds it shuts off without any warning whatsoever and then i start it again and it never shows any error that windows did not shut down properly or unexpected error it just starts as if i ran it for the first time!

i am constantly monitoring my cpu usage spikes through task manager and whenever firefox is open and i open a site or more than 5 tabs or whenever FF loads some stuff usage is jumping up to 60-80% and then when page is loaded it comes abck down to 20%.
but the problem is for the last 8 years i ahve used FF on this very system and it never caused my cpu to spike. i know i ahve a few add ons which cause high ram and cpu usage but i have disabled them as well to no avail

the heat is coming out from the vent and although i can not hear the fan my system is hot as any other system should be. maybe even if i accept that it is overheating that is causing the cpu spike why would it just shut off. also using FF is not the only time it shutsoff i use vlc and while watching movies after the reballing it has also gone off but i understand that is due to cpu spike.

just what could have happened to cpu while the reballing. could the thermal paste beneath the processor be gone? would this cause the cpu to heat and then show high usage? or is ther any other interpretation to this mess.

any advice would be welcome

 

[Ranger4]

Overheating can result in sudden shut downs. The shut down is to protect the CPU from damage due to too much heat. You mention the fan does not seem to be running as you can't hear it. It is very necessary for the fan to run.

You need to gain access to CPU & fan area & clean out any dust & fluff & see if the fan it actually running. If you don't feel confident dismantling it, take it to a reliable computer shop & get them to do it for you.

Continued use with severe over heating will eventually cause the CPU to fail completely.