This sounds like you are having a power supply problem. The power supply is alot like a car battery in that it can have enough power to run the radio and lights but not enough to start the car.
I would get a new power supply and install it in that machine. If you do not know what size to buy here is a handy rule of thumb:
For each Hard Drive, Floppy, CD ROM, DVD ROM you have in your machine Figure on 60 watts each. Then for each additional board you have, video, audio, lan, etc., add 25 watts each for those. Then add 150 watts for the processor and you should have enough. Most machines can do fine with 300 watts. I will not install anything less than a 400 watt just to be on the safe side.
I hope this helps you!
I posted this in XP forum but did not get a response, hence posting it here
Emachines T2040 Desktop
40 Gb + 120 GB
512 MB RAM (256+256)
Summary of my problem:
I had windows XP Home on my machine which was running fine. I purchased 'XP Professional for upgrade' and installed over XP Home . XP Pro ran fine for around 2 weeks but suddenly my computer started giving problem. It would shut down after running for 5 minutes whenever you switch it on. It would not run for more than 5 minutes. I thought some virus has attacked my PC, so I tried do a clean install of XP professional on my PC by deleting the existing partitions, creating new partitions and formatting it with NTFS format. While doing so it copies all the file from XP pro CD to my PC and then does a shut down and restart to install XP but it again shuts down after reaching midway.
I then tried to do a system restore with the manufacturer OEM CD (XP Home) on my PC. It copies all the file from CD to hard Drive and then it shuts down and restart to set up Windows. But when the message comes that windows is starting, the PC would shut down.
I did chkdsk /r and then an exit and then started the windows but again it would shut down. I again did a chkdsk /r and then I installed a fresh copy of XP home from OEM CD and again at the point when it says Windows is going to start, the PC would shut down.
Is there a way to fix this problem by any software/hardware changes or my PC has gone dead. Please HELP.
Thanks & regards,