Can a dell optiplex 745 mid-tower run windows 7?

It should be capable of it, but I doubt you would be happy with the results of actually doing it. The main issue would be whether or not Dell has Windows 7 drivers for that model up, or if you want to try and find updated versions individually on your own.

I often find it helpful to not just consider whether or not something is possible, but also whether or not it is a good idea. In this particular instance, I do not think you would likely be happy with the outcome if you tried putting Windows 7 on that machine.

Will run Windows 7 fairly well, if you stick to 32-bit. Only issue you may have is the ATI 'X' card will not have a native Win7 driver, last they did was for Vista, which will work in legacy mode.

Best answer selected by DELL745.