regztfen, I'm assuming you're using Windows XP. Go to the link below and scroll down to line 314 (left column) and click on "File Associations are Greyed Out" tto download a reg file fix. Save the REG File to your hard disk. Double click it and answer yes to the import prompt. It may correct your problem.

Note: If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem.