Graham Jones is a guest blogger on the Canadian IT Manager’s blog hosted on Technet and also the president of VANTUG. He wrote an article that explained how he had built himself a new computer after giving his son his old one and having some troubles installing Windows Vista. He had built an identical computer to the old one, but was having a terrible trouble with reboots. Here is the full article http://blogs.technet.com/cdnitmanagers/archive/2006/09/28/459624.aspx
I had a similar issue with Windows XP running Virtual PC. Every time I would open a virtual machine (didn’t matter the OS being virtualized), bam, the computer would reboot. I would disable the sound card in the bios and all would be fine, but no sound. It turned out the problem was a case of needing a new set of drivers.