Motzilla firefox will not open-click on it don't even get an hr gl?

I just did a destructive crash on my comp. I have an outdated version of internet expl. I have had Mozilla in the past and it worked just fine. But I have uninstall-ed and reinstalled 3 times with no avail. It looks as if it has downloaded properly but when I try to open it does nothing. I don't even get an hr gl that its trying to. I downloaded Chrome just so that I could use something but really hate it. If you have suggestions I am technologically retarded so please use English. SMART PEOPLE OF THE YAHOO ANSWERS CAN YOU HELP ME OUT???? oh and after 30 min of being on the comp mouse and keyboard are jerky cant keep up and must restart. like now. ugh!!!! thanks guys