I recently had some issues with my Windows install... and I'm not sure what it was.
I turned on my computer in the morning, used it to check my email and the weather before going out to class. Two hours later, I come back to find that my computer is awfully quite. I turn on the screen and see that it looks messed up. I also noticed that my only two case fans weren't on because my fan controller was also messed up.
I figured that a normal restart would fix everything but it didn't. My computer showed the Asus screen like it always does when I start it but it just stayed on that screen. I turned it off and decided to check my connections. That's when I found that my HDs were HOT. I could keep my finger on them but it was noticeably hot.
I feared the worst of course... after unplugging my computer, removing the CMOS battery, unplugging my fan controller complete, and resetting this thingy on my mobo (can't remember what it's called but I remembered from the manual that it resets something in case you had problems). Then it started but gave me boot disc read errors.
I was able to install windows on the same disc but a new folder so almost all of my info was saved. I was able to pull that stuff out and then went on to completely format and reinstall the OS.
And so, here I am. For some reason, my 5 month old installation of Windows just died and I'm not sure why. I never had any problems with it besides the very rare frozen application from time to time.
What could've caused this? Could it have been my fan controller's fault? I'm thinking that maybe that maybe the heated HD caused some errors which killed windows even though all my other HDs are fine. It might of be interest to know my OS was installed on a 7200.9 SATA while the other 3 are composed of a 7200.8 IDE, a 7200.10 IDE, and a 7200.10 SATA.
If your clean install worked for 5 months and suddenly headed south, it's likely got corrupted by a virus or spyware or simply a lack of maintenance, e.g., defraging, cleaning out temp files, updateing BIOS, drivers, etc. Could always be bad hard ware but if you don't do the above regularly, that's more likely the problem.
If you haven't done so, I'd run the diagnostic program from the disk mfg. Not clear but if your machine is up and running now, it's always possible there was a problem with you hard drive, possibly because of the heat, that was fixed when you reformatted it. I've had hard drives get flakey on me in the past and formatting fixed the problem. I'd definitely back up all my stuff on a 2nd hard drive and then back up any files that were changed everday. I found a nice program called GoodSync that is really good for backing up files, There is a trial version, I think I paid $20 for it, but if you don't have any other programs to back things up, it would be worth a try.