I never heard of this term before, so i took the liberty of google-ing it... i must say, the results were... epic.
Possible meanings:
1. an extremely shitty computer where everything is built into the motherboard so nothing can be upgraded.
2. A computer manufacturer accidentally mispelled its name on all of its company letterhead. It was supposed to be Comcrap, but once it was printed "Compaq," it was too late to change it. They make computers that are vastly overpriced, underpowered, and generally unreliable.
3. Makers of PC computer systems that are made by sweatshop workers in third world countries in textile mills.
Obviously those results are jokes
Here's a serious one (too long to paste it in here)
http://www.webopedia.com/TERM/C/Compaq.htmlSuffice to say, it's a company just like Dell and others. Doesn't seem to have anything to do with a hard drive or partition.
Does it actually say "Compaq C" when you look in properties or something ?