If your PC has an HDMI output then you can use 1 or 2 cat5 cables with the appropriate adapters at both ends of the CAT5 cables. Just google "HDMI over CAT5"
The CAT5 cables cannot be used for any other purpose.
I was actually going to ask a similar question, so not meaning to hijack. I'm having a new house built, and met with my builder tonight. In the house I have, I've actually ran HDMI cables to the different rooms. He suggested using CAT 5. Is there any problem with signal loss or anything?