I got a Blue Screen Of Death on reboot.
Where are events like this logged on Windows XP and how can I view the history of the BSODs?
Control Panel -> Administrative Tools -> Event Viewer
BlueScreenView by Nirsoft is a much better solution than Event Viewer; Event Viewer does work, but this provides the information in a better format and much faster.
In Windows XP/2000/NT4, sort the System event log by the 'Source' heading. Look for an event source of SaveDump. In Vista/7/8 look for BugCheck. There will be a status code that you can look up, such as 0xC0000050. Change the C to a 0 before searching it on the web.
If you have your pc set to capture minidumps, you can try Who Crashed, it automates looking for some of the common causes of BSODs.
If the event log doesn't help (which it often doesn't for BSODs), and you're feeling adventurous, you can also set your system to automatically save a minidump of the crahs, and then use WinDBG to determine exactly what caused it. See http://elliottback.com/wp/how-to-analyze-windows-xp-bsod-minidump-files/ for an example