Acrobat X on Dell XPS 8700 - Need to Activate again by mistake

Hi.  I have been trying to upgrade one of our desktops, which is Dell XPS 8700 that was purchased in Sep. 2013.  We have also purchased Microsoft Office 2013 Pro + Adobe Acrobat X Standard, as OEM software, installed by Dell.  Today, I have been trying to upgrade it with an SSD drive, and I have accidentally downloaded Acrobat XI from Dell Digital Library, which automatically replaced the Version X.  Realizing my mistake, I had 'System Restore' back to prior date, and now Adobe X Std is screwed up.  I had managed get the installation file (Data1.cab) from an installation CD from another computer.  So I had successfully 'repaired' Acrobat X Standard.  However, it is now asking me to 'Activate' it.  Unfortunately, I do not have the Serial No. as the software was pre-installed by Dell, and somehow I had not seen it either (It's possible that one of my co-workers has mis-placed it).  Is it possible in anyway, that I can get the proper installation Serial No.?  I can provide an old email receipt from Dell, matching the the serial no., etc.  And the Ethernet card is still the same.

Thanks for your support.  jjjcb