I have 2 desktops, a BUSINESS PRO DC7900 and an ELITE 8000.The 7900 came with the complete dvd kit . Included was a XP PRO, sp 2 and 3 . The 8000 had a similar kit with a WIN 7 PRO. I have seen the OEM WIN 7 PRO 32 bit with 2 different part numbers. The 7900 is #650432. The 8000 is #589203. They are both marked as WIN 7 PRO SP1. The only outward difference is the BLACK and WHITE color combination. black over white versus white over black. Are these 2 CDs EXACTLY the same despite the 2 different numbers? I would like to use the 8000 os cd in the 7900 tower to change from XP to 7. Is this possible or do I need to buy a complete DVD KIT for the 7900. I have a kit with the WIN 7 cd missing. I was under the impression that only the PLUS CD was model specific. The others were universal. I tried to downgrade the 8000 to XP following the PLUS CD. It did not work as XP is not in the OS's listed. Perhaps I am wrong. Also the other WIN 7 versions CDs are also missing. I only have WIN 7 PRO to use as that is the only CD I have. Advice please. I can get a 7900 kit from EBAY. I cannot find a WIN 7 PRO specific to the 7900 if that is really needed. I would rather not have to buy another kit just for the sake of ONE CD.