help help help......i need your help

[nikhilmdhk]

I have a problem on my pc hardware, I don't really know if it is the graphic card, the memory, the board or the power supply of my pc. here's the detailed explanation of what had occured to me.
it started 2 weeks ago, when my brother and i were watching a movie. After 4 hrs of wathching the pc shut down automatically. So we thought it just overheated. But the day after that happening, everytime i start the computer it's automatically shuting down. First it shut down after watching 15 minutes movie. Then it shut down after 10 minutes running macromedia flash, so my brother as the technician of the pc decided. to take a look at it and he said he found that the graphic card(gforce fx)was dead(he thought). so we decided to buy a new graphic card(gforce2 mx). but when we try to plugin the gcard, it's not running. the problem still exist. Everytime I turn on my pc for 15 to 20 minutes it will turn off automatically. By the way my operating system was windows xp. My brother thought the main board is the problem

[jason2074]

Have you run any or your Hardware Temperature Monitor to see any indicator such as speedfan? If yes, please post an image.
To post the image : http://www.computerhope.com/forum/index.php?topic=61232.0
IF you don't have speedfan : http://www.heroturko.org/s/SpeedFan-440-Measure-CPU-Temperature/
If you have a spare computer to work on, Download speedfan(if you dont have yet) and save it to flashdrive and copy installer to the faulty computer and install it to be able to save time before it turns off again. If you already have HW monitor, Run and post an image.

I assume your brother had already gone cleaning all certain parts of the machine from dust.  

[jason2074]

Also forgot, to please post computer specs

[Allan]

I've deleted your duplicate posts. Just ask your question once and then stay in the same thread. Thank you.

[Cliffmarcum]

I would check and make sure all your fans are still running inside the computer could just be a simple over heating problem. Make sure you clean out the fans and the computer with some compressed air.  but more specs on the computer would help a lot. let us know what the problem was if you have fixed it.