After looking over their web site, it appears that what they are doing is using a remote connection to do a repair installation of Windows XP.
If you look at their FAQs, you will see that they say that they do not sell keys to the program, but that you are paying for a one time repair.
If they are doing what I think, as stated above, there is, of course, no program to sell and hence no keys.
If you have frequent problems with the computer, check into built in repair programs that come with XP such as check disk and system file checker.
Check disk: http://support.microsoft.com/kb/315265
System file checker: http://support.microsoft.com/kb/310747