I have a Pentium4 1.6 GHz CPU placed on a Manli Intel 845D based motherboard. It has onboard AC'97 Sound Card and I have nVidia Riva TNT2 32 MB AGP Card, A 20 GB HDD holds Windows 98 as OS and No other software as such. The problem is that whenever I switch ON my machine it goes fine through the POST and all but when it is loading Windows98 my display goes OFF everything just freezes and my HDD and CDROM LED's glow steady and then even if I press Power or Reset the PC does not take any action. I have to Switch OFF the mains then only the PC would shut down. In Safe Mode, Windows gets loaded but after sometime the same thing happens. Thinking as OS or driver problems, I formatted and re-installed the OS, but nope, the same thing goes on continuosly. I also tried replacing IDE cable of the HDD but same thing happens, RAM slot is also changed, Can Anybody please help me out on this issue?

Go into safemode and check the bootlog.txt. It might tell you what is causing the crash. You can also do a step by step starup: Click Start, and then click Shut down. Click Restart, click OK, and then press and hold the CTRL key until the Microsoft Windows 98 Startup Menu appears. Enter the number for Step-by-step confirmation, and then press ENTER. Press Yes for each device. Note what it is loading when it crashes. That is your problem. I would bet it is the video card, but the above steps should tell you.

I have had similar problems.. Could be a bad sector in your hard drive. Nothing much you can do about it but get a new HDD. Seeing as how you reinstalled and all that, that is one of the only conclusions I can come up with. You can try reformatting and removing any and all partitions, create a new logical dos partition, then reinstall os on top of that. If you still get problem, get new drive!

Doc memory tester You might also want to run scandisk 'thorough' on your hard drive.

You can run scandisk thorough from dos by typing: scandisk c: /surface

Thanks, all of you for giving me such a quick response. But the problem is quite different, I think I have sorted it out this morning. The CPU Fan is the culprit. The small piece of wire that gives the power supply to the CPU Fan is not proper. It works sometimes or doesnt work. Therefore the CPU Fan does'nt rotate properly. According to me whenever Windows is loaded the CPU usage increases, but since the fan is not rotating properly, CPU heats up and causes that weird thing. Only now I have to wait until I get a new fan, then it will be confirmed, anyways. I will surely post if I notice anything absurd or If I require u ppl's help. Thanks a lot