Please state your exact Adaptec scsi card info. What is the ID number on the card? Exactly, what card do you have? What is the firmware version currently showing on card. (boot into scsi utility to get some version info) Have you ever changed/upgraded the firmware on this card? When was this card manufactured? What scsi drives are you using? Ultra320 scsi? 160 scsi?
It appears you're trying to make the AIC-7870 PCI SCSI Controller act as an "emulated" drive, for 64 bit, on the 2940. Why?
You are on Windows 7 now? Was your card running on Vista x64 with x64 drivers? Did you upgrade to Windows 7 or clean install Windows 7?
Are you saying x64 drivers you have don't work with Windows 7?
Did you try this advice & NOT find x64 driver?
"in device manager, select the SCSI adapter, click "Update driver", "Browse my computer for driver software", "let me pick from a list of device drivers on my computer", uncheck "show compatible hardware", and select "Adaptec" as Manufacturer and "Adaptec AIC-7870 PCI SCSI Controller (emulated)"
With more info, I may be able to help you.