Cannot open files

I must have created a problem on my computer. Don't know how I did it but how do I get it back to normal. Adobe Acrobat is attempting to open files. Each time I try to open a file I am given the message that Adobe cannot open this file. I am running XP on a Dell 8600 lap top. 1 gig of RAM and a Centrino processor. Thanks

 

Are they all files? Including, .exe, .doc, etc? Or just .pdf's?

If it is just .exe files, then give this link a shot:

http://windowsxp.mvps.org/exefile.htm