If you check the name of your driver, what is it? For instance "HP LaserJet 8150" or just "LaserJet 8150"? The reason I am asking this is because in the driver inf-file the name of the driver is "HP LaserJet 8150 Series PCL6" and if your driver name is different then windows wont recognize it. If your drive name is different then: open the hpc8150c.inf file with notepad and replace all "HP LaserJet 8150 Series PCL6" with the same name as your driver "HP LaserJet 8150" for example. Save the .inf file and then try again
As described on:
http://superuser.com/questions/23703/installing-additional-printer-drivers-x86-on-windows-7-x64I hope it helps, good luck!