I have a Compaq desktop which I have had sitting up for a while, it isn't but maybe 5 years old. I say it's been sitting up for about a year. Well anyways, I decided to break it out and get it going again. I got all my hardware, the CPU, HDD, 1GB DDR2 RAM, and a CD drive. I put everything back in properly and it does not POST beep at startup nor does the monitor get any signal. Anyone have any ideas what could be causing this problem?