Anthony, There are at least 2 of us W2000 users here who were unable to launch Poser 5 after installing the patch who are now able to run by dropping back to the old version of tpkd.sys. I don't understand why you don't advertise this as a workaround until you guys figure out the ultimate solution. If I had waited on CL I would have been down for 3 days now. If you're scratching your heads on why some W2000 users are affected and not others, I'd take a look at who has installed W2k SP3 and who hasn't. I have, and I have the problem. Buck