Oh man..i'm so frusterated

This evening I unhooked/unplugged/disconnected (and while i was at it i even cleared the CMOS ) everything in my computer, because i wanted to clean the massive amounts of dust that was blanketing everthing. Anyways i was very organized and carful with all the peices. With my handy User's Manual by my side, i proceeded in putting everything back together (something which i had never done before). In the end, everything 'seemed' to be in it's proper place but i was wrong. I first started up the computer, set the time and date (only) and continued booting up. It frooze after the windows loading screen finished. It slowly got worse until i can't even get into my bios without it freezing. Any suggestions?