I screwed around with different partitions and upon restarting my laptop got a blue screen that said "UNMOUNTABLE_BOOT_VOLUME"

Nothing I tried got me past it, so I decided to re-install Windows Vista from the CD. However, when I try to select the partition to install it on, it says "Windows is unable to find a system volume that meets its criteria."

Please help me; this is unbelievably frustrating. I need my OS back.

I am not sure if you will be able to recover any lost files, because if the partitions were that badly messed up, a recovery installation probably would not work.

My suggestion is to get Darik's Boot and Nuke and run it from a bootable floppy or CD:
Darik's Boot and Nuke (Hard Drive Disk Wipe)

Reformat the entire hard disk so that it is all free, unpartitioned space. The quick wipe should suffice to do this. With a clean slate, it should be no problem for Vista to recognize and write to the HDD.

Rodents210, thank you for the reply and help. I've recovered my important files via my Linux OS so I won't lose anything important
I'll try this and post the result.

just delete the partition and start from scratch. You can always partition the drive after using vista inbuilt partition tool or partition magic

I have 5 hours to go in the DBAN process.

That is overkill no need to do that