boot up problem

[sliders]

Hi, my PC sometimes can boot and run windows98 normally, then crash after a few minutes. If that happens, i have to wait at least one hour so I can turn on the PC, then crash again.
But sometimes, the boot up process is stopped, after i turn on the power, then i can hear the memory counting, but the monitor shows nothing not even the BIOS and no sound of harddisk processing (crash), can anyone help me why, is it the RAM is bad, or else.?

[Rick]

The fact that you can boot and then after a period of time it will crash .
Then after it cools you are able to reboot till it gets warm again.
Leads me to think you have a Heat problem.

Check your Case, CPU and power supply Fans.
Make sure they are working.
Clear out any dirt and dust build up in the fans, cooling vents and the CPU heatsink
Make sure the case air inlets are clear or proper air flow