Hard Disk Boot Failure

My computer was crashing frequently whenever running video games and I figured it was from the video card overheating so I opened the case took the card out blasted the whole thing with compressed air and the video card as well and then put the card back in, nothing else was dissconected. When I turned the power back on I got the error "Hard disk boot failure, please enter the boot disk and then press enter" so I put in the boot disk and it said "Windows cannot detect the hard disk, it may be dissconected" and then I looked inside my case again and there is a thin red cord I didnt notice before that was hooked up to the hard drive but not to the motherboard, it is the SATA/RAID cord but I don't use that configuration, does anyone have any clue what might have gone wrong?

After reconnecting the hard drive you might have not connected it properly. Just open the case, press the cables into the slots properly and then try to boot. The fact that your system cannot detect the hard drive itself indicates that the hard drive is not connected properly.

I say this because this has happened to me that I opened my case, then changed the CMOS battery. In this course, unnowingly, the hard drive connction got loose. My PC could not detect it and the same error as yours. I then opened it and pressed the hard drive cable hard inside and then it was detected.

This is a classical myth, after opening case and meddling with hardware: "nothing else was dissconected" ...

Usually (or almost always), something get disconnected or at least partly disconnected Hence re-checking all connectors before closing the case is always a good idea. Partly disconnected cables give you nightmare problems you can't solve