PC Trouble

[Reine]

Recently, I moved my PC over a bit to make room on my desk so I could work on my art contest challenge, and to keep a picture on screen that I could refer to, but after moving it over, for some odd reason, I find that it will no longer load, and just loudly beeps thre times and does nothing, and the moniter doesnt even turn on. Ive opened the case, and nothing seems to be disconnected (But there is a large amount of dust)

It has no access to the internet, so I doubt it could be a virus, so would anyone have any idea what could be wrong? I appreciate it

EDIT: Its working, I put in a floppy disk and turned it on, and i loaded and went to the "NON SYSTEM DISK" thing. I ejected it, and it loaded fine, I then restarted the machine, and its working...wonder what the hell went wrong with it..