problem opening pdf files from internet

I have searched the archived files but have not find the solution to my problem.
I have one computer (dell laptop, running Windows 7 Profesional, 32 bit OS) and when I go to my website to open a pdf file, I get a dialog window marked File Download, asking if I want to save the file. It also states, "The file you are downloading cannot be opened by the default program. It is either corrupted or it has an incorrect file type. As a security precaution, it is recommended that you cancel the download." Additionally, a blue hyperlink offers, "How can I decide what software to open?" Clicking on that takes me to microsoft suggested options to fix this. None help. I have gone to the Adobe website also for suggestions and am still stumped.
On all other computers, running Win7 or XP this doesn't happen and the computer opens the pdf files as desired.
I am running Acrobat 10 reader and have Acrobat X Professional.
Thanks