PC Failing to boot

[Kaelan?]

So my PC has been completely failing to boot properly lately. It only started this morning, was working fine yesterday.

Now all it does is either ask me to run the startup repair, which doesn't actually do a whole lot, or boot windows normally, which will cause it to go all the way to the windows logo, seem to be working fine, then right before loading the desktop I get these clicking noises from my OS drive and it'll just reboot.

It will also every now and then give me a

Verifying DMI Pool Data ...........

Boot From AHCI CD-ROM:
DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER

randomly while booting. Sometimes it goes away after a reboot, sometimes it comes back.

I'm on Win7 with 3 HDDs, one SSD with the OS and two regular drives in Raid0 as my data drives.

Anyone know have a clue on what the could be causing this?

[Jefe]

Those noises coming from your HD are a clear indicator that it's dying and need to be replaced. Since you have it set as raid0, I think you're boned ;x

[Kaelan?]

The two regular drives are in raid0, the SSD is on its own. If it's just the OS drive failing, I should be able to replace it without worrying about the stuff on the data drives, right?

[Jefe]

That is correct. Mirror the faulty HD and you should be set to go. One thing though, SSD don't spin... so it has to be one of the raid ones. ;x

[Kaelan?]

So upon closer inspection in the BIOS, my boot order had somehow gotten screwed up and it was trying to boot off the wrong drive. I've fixed that now, but I'm still getting those "DISK BOOT FAILURE" messages (though without any weird clicking this time). Will try to reformat my SSD and put a clean install of Win7 on it, to see if it's not just corrupt system files or something like that before throwing it away entirely.

Edit: So yeah, formatted the drive and made a fresh Win 7 install and it's working fine now, starting up without any boot issues. I guess it really must have been some corrupted system file or something. Glad I don't have to actually replace the drive itself, that would have been a pain. Thanks for the input anyways~