This is a boot problem that seems to go beyond the easy fixes. iTunes 8 had just caused my computer (Vista SP1) to BSOD, and like an idiot, I hit the reset button as it was backing itself up. The computer reboots to the "BOOTMGR is missing, press Ctrl-Alt-Del" message. Thinking I can handle this, I get out my install CD, switch over to booting from the DVD drive, and go to the repair option.
This is where it gets weird. I click on "repair startup errors", and within less than a second, it reports no errors found. That can't be right, so I tell it to use system recovery to go back a day. I reboot after that, but without the CD it still gives me the same error message. I go back to booting from the DVD drive, and use the command prompt "bootrec /fixboot". It says succesful, but still won't boot without the Windows disk. The really strange part is that if I have the disk in, and tell the computer to boot from the disk drive first, but then don't press any key when I get the message "press any key to boot from CD or DVD" it very politely boots straight to my Windows, everything there, no problems except that I don't think I can connect all the way to the internet (I can connect to my router, the same one I'm using to write this, but not the second half of the way to the internet.)