Hello, what I would do is uninstall, delete all the drivers, and reinstall with the PCL 5 driver, sounds to me like there is a driver conflict. Also, it wouldn't hurt to do a firmware upgrade. The workstation that is connected to the printer, was that up graded or did the whole machine get swapped with a 7 machine? Also, are you remotely connected to another enviornment? Ex. you have a win7 PC but are remoting into an xp enviornment, to do work?
Hope this helps....