I've seen the green lines with video cards that are burning up (bad fans). That makes me wonder if you've got all the connections made properly. Those little ribbon cables and clamp sockets can be tough.
One other thought: did you go into the Device Manager and Remove (Uninstall) the old 2600 graphics adapter before you shut down and switched the graphics cards?
As for whether the new card is compatible, have you tried contacting Lenovo Tech Support?
I would suspect that if it fits in the laptop it would work.
For the others looking:
New Graphics card, can't get it to work