Do the Safe mode boot as stated above, and if it reboots again, it's either your Memory (RAM) that has a bad chip on the RAM. You can boot, but when a program addresses an area in the RAM 2000C-3000E or some such address and crashes.
Do you have ECC or NON-ECC Ram? Just wondering. If it's not the ram, it may be the motherboard. Heck, the HD could be dying. Maybe your swapfile is sitting ON the bad block on the HD.
Also try this (if you can without rebooting):
Lower your swapfile to a SET amount of 80MB. and reboot and try something. This sounds odd, but it's a trick I've used on finding bad HD's.
Is your Ram chip 2 pieces? 2 128MB chips? If so, remove one, and boot, load Winamp. Try this with the other chip swapped out as well.
If one way works, it's your RAM.
Let us know. (Print out these steps)
