I appreciate your help and patience. I deleted the prescribed files, deleted the registry entries (OpenMP was not in HKEY_CURRENT... but was only in HKEY_Local), turned off virus protection, and used the downloaded 4.0 installer. Now, I get an MD Burner window that opens saying "a fatal error has occurred. If rebooting does not solve this problem then re-install the software." Rebooting does not solve the problem. Does that mean I should remove everything and reinstall again? hmmm, let me see: (Insanity is doing the same thing over and over again, expecting different results.) thanks for any advice..... (I'm using an XP machine (SP2), with more than the minimum requirements stated by Sony)