I put my laptop to sleep last night, and when I woke up this morning... it didn't. So I tried to reboot, and everything went fine until it got to the Vista splash screen, where it's supposed to display the logon. Here, it hits an endless loop:

1. Display the cursor with the blue spinny thing that replaced the hourglass, for 5-10 seconds
2. Display "Please wait..." for about half a second
3. Screen flashes to black, then quickly back to the Vista splash screen
4. Goto step 1

The whole time, my hard LED is on almost non-stop. I can boot into Safe Mode... sometimes. Sometimes it'll load all the drivers, then sit there for about 10 minutes, spinning the hard drive non-stop, then reboot with no warning.

I tried booting to Last Known Good Configuration. Didn't fix anything. When I've managed to get into Safe Mode, I tried running CHKDSK. Didn't fix anything. I tried running System Restore to each of my last two restore points. Didn't fix anything either time. I ran a virus scan. Didn't find anything. I tried calling the manufacturer (Alienware), only to discover that my warranty expired last freaking week and now I can't get it fixed without paying exorbitant sums of money.

I'm about at my wits' end here. Has anyone seen this problem before? Does anyone know how to fix it? Does anyone know a solution that does not involve reinstalling the OS and losing an entire year's worth of program installations, Windows Updates and configuring and tweaking things until it's working just like I want it to?