In my own experience, 90% of the time that error is caused by conflicting hardware. PCI cards or drivers using the same IRQ channel, and competing for it, causing a Hardware Conflict. This is easy to spot by right clicking Properties on MY Computer, goto Hardware Tab, then Device Manager. See if there are any yellow question marks on any hardware, and that'd be a good sign. Uninstall drivers and reinstall, or disable something to resolve it. I've actually never had that issue with something like SP2 upgrade, it usually happens with high-end games that demand a lot of power. But, yeah, def. check the Device Manager.