I am unable to delete a decrpter program from my computer. I can not install the newer version until the old one is deleted. Can someone help!!!!!!!!!!???????

Did you use ADD/REMOVE programs in control panel to remove it? If so, you can safely delete the working driectory (normally in C:/program files/{program name] etc. The program may left invalid/broken registry entries so may have to delete them manually, but you to have to be careful.