If you have a computer system that is experiencing random errors, it may be worth testing the memory. memtest86 is a tool for validating the memory in an x86 computer. The software is a bootable CD which immediately runs a battery of tests on all the memory in a system. The tests take a long time, but after they have run you can be pretty confident that the memory is working. I recently used it on a laptop that was rebooting randomly. memtest86 determined that the top half of the system's memory was not working well. When I opened up the computer, I discovered that one of the plastic clips that keeps the second DIMM firmly in its socket had broken. I jury rigged a solution using some glue and a bit of plastic. I then re-ran memtest86, and it passed all the tests. The system has been working fine ever since.