An Optiplex 790 that came w/win7pro. virus messed it up so bad had to wipe and start over. It didn't have the on-disk factory restore. Media is long gone. I have the key# on the side. I've tried a dozen ways to rebuild it and MS blocks me at every turn. I could download win7 from MS but not with an OEM key. I tried a win8 disk from another Dell but doesn't like the key. Have win7 loaded but won't activate from a retail win7pro upgrade dvd and I have the key with that but it doesn't like it. Tried the key from another Dell that came with win7. downloaded win10 but it doesn't like any key I have. don't want to order and wait days for Dell to send a new disk. Somebody get me out of this MS rat maze before I go crazy. please.
Thanks.