I have an ibm netvista computer that keeps restarting. I've tried loading multiple operating systems, and only DOS will run, windows doesn't make it past the initial loading screen, and several versions of linux restart during hardware detection. I first thought it might be an overheating problem, but DOS has no trouble loading up any ideas?

dont forget dos is not like windows its takes less time to load therefore your cpu wont heat up so much make sure there is no dust inside the case and the fan is on the cpu right

the case is quite clean of dust, and the CPU has the heatsink+fan in place.

Dos uses very little memory (< 1mb) . Try a memory tester. Doc memory tester You might also want to boot from a win9X floppy and run scandisk and scandisk /surface on the hard drive.

I second the memory test, but I've had very similar circumstances on a PC which is about 2 years old and it was the CPU that had gone bust.. dropped in a new one and all worked lovely. Also you havn't mentioned the condition of the motherboard - check that none of the capacitors on the motherboard (small black round things generally with silver tops) are leaking. I've seen this a lot and that causes a very unstable system...