Desperate female seeks computer nerd! i need help!?

haha im quite the comedian, eh? i have a desktop its a dell. idk the type or model or whatever.... i got it off of craigslist an it worked perfect. it has no viruses, never been on the internet, i only used it to play games. but anyways. everything is connected right. and when i turn it on, the monitor says no signal in a little gray rectangle box. the comp kind of clicks. it WAS beeping 3 times, but i looked it up and said i needed to make sure everything was clean and fit in right. o i did and theres no moe beeps. the licking sounds like its coming from the hard drive. i seriously need this fixed....know whats wrong?