Yes you can, MightyJoe. I forget how but I know I use to do it .. I know it had to do with D2Loader.. And I remember it being a pain to set up. Does anyone else remembers how to do this?
It requires D2Loader and Onlyer's CD-Key Refiller utility. There are instructions in the D2Loader Readme, I believe. If not, the CD-Key refiller should have a Readme.
Don't remember where to get it.. MAYBE hellmonkeys site? (not sure if it still exists havent checked in a long time) but i believe it lets u replace ur current CD key with another one