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?

Looks like you accidentally unplugged SATA cable from board. Make sure you have one end of SATA cable connected to motherboard and the other to the drive itself, with another cord (Molex or SATA power) connected to the board and the drive. I hope you DO have Serial ATA hard disk?

If the 'red cable' is connected to the hard drive, but not the motherboard then you can be sure you need to plug it back in