Well, I fixed it. Just started in Safe-Mode and scheduled check disk for the Windows drive. Rebooted, computer Checked Disk with 0 output, and then it booted up like normal. Rebooted twice more to double-check that the computer was indeed working. Strangest thing I've ever seen.
I have a Compaq Presario F730US. Every time I try to turn on the computer, Vista's "Logging Out" screen appears and the computer pinwheels, never gets past that.
Can somebody help me? I've googled several combinations yet it seems nobody has posted about this problem.