Optiplex 990 sff - Dual monitor - Windows 7 Pro

Good day people..

So I have an old optiplex 755sff duocore- which is good, but sometimes it feels slow - with 2 exact same monitors - one conected to VGA and the other to below pci card DVI ..so I used them extended - win7pro- all working perfect

I was able to get a Optiplex 990sff cheap i5- 3.2hz 8gb win7pro -- feels great for minor office duties - that one comes with VGA and display port - so I opened the 755sff removed the pci card-dvi, installed it in the 990 and nothing (it recognized the card and it stated "ready to use" - but monitor is black - no signal

put it back on the old pc, and it works right away

I search online without much help -- installed several drivers, updated BIOS (no option to enable dual monitor) as per some google search, nothing..

is the card not compatible? can i get an adapter from dvi to dp (would it work?) if not, what pci dvi card can i get? will not be for games or movies - just data entry

Thank you for any help!