I have been running vista ultimate 64 stable for several months now on a new build. However, after downloading and installing service pack 1, it sent me to a blue screen, did a memory dump, and then the computer would not reboot again. It powers on, albeit just the case lights, and fans but will not post to BIOS, just a black screen. The monitor doesn't even come out of sleep when the computer is powered up (tells me there is no signal). I have removed all but 1 gb of ram, disconnected the HD's and all other peripherals and tried rebooting again, but nothing changed. Could the update have killed my motherboard? Any suggestions would be greatly appreciated.
msi k9a2 platinum
4 gb kingston hyper X
coolermaster pro 1000W
two HIS 3870's in crossfire
two samsung spinpoint T series 500 gb in raid 0
Once done/successful: Since there's not much more information than "It Doesnt' Work", then I would start up into Safe Mode, clean out all the existing device (Audio/Video) drivers - Since you have Crossfire, I'd remove one card while doing it. Make sure it's all clean, boot on the default Vista drivers, and them go back through and reinstall your ATI video drivers and the Crossfire stuff.
Try resetting your BIOS and see if it posts. If so, then do the startup repair like Scotteq posted if it won't boot.
You need to make sure you update all of your drivers before installing SP1 - especially your chipset, RAID and sound drivers. There are numerous drivers that are incompatible with SP1, and they must be upgraded before you install.
Oh, and make sure you update your ATI drivers. Seems a lot of people had problems with the 8.3 and SP1. 8.5 is out now, and 8.6 coming soon.
You may also want to upgrade your BIOS while your at it. Be forewarned, though, that you'll probably have to call MS to reactivate Vista if you do. It's quick, but annoying.