I stupidly tipped my computer a little to clean out some dust underneath the hard drive... While it was on. My graphics card was a little lose and fell out. The PC would boot normally but the keyboard, monitor and mouse wouldn't respond. I put the graphics card back into place and the monitor switched on when I next tried it. There shouldn't be any problem with the hard drive, since my operating system booted... but I still can't use a mouse or keyboard. Oh, also, I tried the USB ports in the back and front of the case, neither worked. However a CD tray did. I tried a spare mouse and keyboard, which lighted up. The ones I currently use didn't even display a Caps Lock button or laser for the mouse. The ones I tried didn't respond to me pressing Scroll Lock, nor did the cursor move when I moved the mouse though. Is it likely that the motherboard short circuited? Should I try buying a new one? I'm not really familiar with installing components, the last I tried (graphics card) wasn't very successful, as you can tell.
Any suggestions on how to get a response from mouse or keyboard would be appreciated, or even where to get a new motherboard/ check specifications would be great.