Eve Patch Spaz
After a large number of PCs stopped working following installation of the new Trinity patch for Eve Online, developers CCP were able to confirm that the patch deletes the boot.ini file from Windows XP machines. What this means is that XP users who downloaded and applied the patch within the first few hours (the patch has now been taken down) cannot reboot their PC.
If you're in this ludicrous predicament then you're probably not reading this post. However, the "solutions" thread can be found on the Eve forums here.