My time is $40, but exactly right, before parts. You can cut the labor cost out completely if you're mechanically inclined, but I have to keep reminding myself that an awful lot of people aren't.
If more people were mechanically/technologically inclined, we'd be out of work.
Depending on which version and service pack level of Windows is installed on the HDD and whether or not old and new lappies have similar hardware, you may be able to get away with transplanting the drive, running a repair install from the Windows CD that came with it, and reinstalling the drivers for the new/different hardware.
Non-custom laptops still come with OS CDs?