Adobe Acrobat/Reader PDF File association advanced problem. Windows XP Pro

Ok, I'm having an issue with a client trying to open pdf files. Every time he goes to open them it says "windows cannot open this file" And tells him to select from a list of applications to open it with. Easy so far right? Well when you select Acrobat to open it with it opens just fne, problem is even if you check the box to "always open with this program" he has to go through all those steps again next time he wants to topen it It never "holds" the association. So I did some digging around and tried another solution. I go into "My Computer" logged in as a domain admin that I have also made a local admin just to be safe. I select "Tools" "Folder Options" "File Types" and there is no pdf file listed in registered file types. So I click "New" and add the file type as .PDF and associate it with Acrobat 7.0. The PDF entry appears at the top of the registered file types list. Heres where the big problem comes in. Once I select Adobe Acrobat 7.0 frm the list pf applications to open it with and hit ok the icon for the pdf file type doesnt change to an adobe icon like it should, and on top of that the "APPLY" button at the button to apply and save changes is still greyed out so it wont even let you save the newly added file type. Once you close the window and come back...no pdf entry again. I've also tried looking in the preferences in adobe acrobat but it doesnt seem to change anything either. What the heck am I doing wrong here? Thanks for your time.