What is going on with my COMPUTER? It RANDOMLY shuts down. I don't know how else to describe it, sometimes it immediately shuts down right after I BOOT it up, some other times the main machine STAYS running but my screen gets no signals from it forcing me to shut it down.
What is wrong? Can someone suggest some solutions?Could you provide some specifications about your machine, such as the CPU type, SPEED, power supply, brand, or even a general model? eMachine T6410 ( I believe )
running Windows XP Home
that's all I know so far See, if same thing happens in Safe Mode....restart computer, and keep tapping F8 key until menu appears.3 most common causes :

Heat
Bad RAM
HDD issues

For the heat issue open the case and MAKE sure all fans are working...

For the RAM issue DLoad and run MemTest...let it run a few hours. Any errors and your RAM needs replaced

For the hard drive issue: DLoad and run the FREE diagnostics from the drive manuf. site...this will let you know if the drive is healthy.