Besides Firewall, the only thing I think that maybe a problem is buffer overflow protection issue. I would expect that it could have issues with copy protection schemes.. especially if logic does something like decrypt code in memory and then execute it. This would be a real problem on cpus that support the NX bit - IE AMD 64 bits and newer 775 P4 and Xeons. As far as I can tell it now, my problem now seems to be fixed with turning off XP's firewall. Stewart