Illustrator CS5 .ai files won't open

RobertButler

Everything was fine a few days ago opening .ai files with Illustrator. Now I can't open any .ai files most of the time. My computer will start up Illustrator but no file will load. Occasionally, the files I tried to open will all open and load at once after a reboot. But after the reboot, the files will not open again. I uninstalled Illustrator and reinstalled, however, this has not fixed the problem. I'm also having trouble exiting out of Illustrator, it won't let me close the program at times. I'm using a HP Notebook with the Windows OS. Any ideas of what to do?