my iMac is crashing:(

Hey there. I am trying to fix my iMac. When you turn it on it chimes and gets as far as the grey apple and the flashing spinwheel. I followed other instructions on how to fix it; I inserted my Mac OS x Install DVD and did the "C" thing and it went to my desktop, but now no programs will open and when you put the mouse over the fider bar or the application icons they kinda blink, they disappear and reappear and nothing happens when you click on them. Not sure where to go from here. Any suggestions? I am so surprised I am having trouble with my iMac...had it for over a year and it has never even locked up.

From what you described, I really have no idea what you did?

Please try a safe boot, an Apple-recommended procedure that does a hard drive repair automatically:
Mac OS X: Starting up in Safe Mode
How to Use Your Mac's Safe Boot Option