Operating System is missing?

[DuckButter]

When I boot my computer, white text on a black background says "Operating System is missing". This started after I went to the bios and set the clock of my processor back to stock speed. I've tried using the bios' default settings and a plethora of other solutions. I do not have my Windows 7 installation disk, I have a Windows 7 repair disk though. Error code 0x0 and the diagnostic said something along the lines of repair partition table. Help please!

EDIT: I went to clean the partitions and noticed that my hard drives are formatted at RAW, I don't know if this is relevant or not

 

[Emerald]

what where your hard drive settings in the BIOS? IDE, AHCI, or RAID?

 

[DuckButter]

what where your hard drive settings in the BIOS? IDE, AHCI, or RAID?

They were in RAID before I converted to original bios settings. RAID 0 to be exact

 

[Emerald]

if the OS was booting while it was in RAID they need to stay in RAID to be able to access the data