Marco, The EXACT same thing has happened to me. I have contacted CL Tech Support, (copy of e-mail at end of this post) but it takes a while to get a response. Meanwhile, I am without Poser 5 (fortunately, none of my other programs seem to have been affected). I have tried everything I know to restore the old working environment, including restoring my System State data and program files from last weeks backup (I backup the whole system on a weekly basis). Even after doing this, it still freezes. My OS is on a separate drive from my Applications like lalverson's, so that's not it. I hate to think of having to reformat my C: drive and reinstall W2000. Your workaround might be preferable to that. One thing... I had taken advantage of Poser 5's library file system capabilities to customize my file structure. Because of this, I ran into errors when I tried to install the figures part of the patch, and think this may have been part of the problem. By any chance did you experience this too? I'll try Penguinisto's suggestion next. If anyone has any other ideas, please post them here. I'll post any progress here also. Thanks, Buck copy of e-mail to CL tech support Hi, I have a Win 2000 machine; Pentium4, 2GHz, 1.5Gb RAM, I was running Poser 4 and Pro-Pack. When Poser 5 was released, I installed it in it's own directory and both versions ran fine. Last night I downloaded and installed the Poser 5 patch (the two part version). Now, when I try to start Poser 5 the system hangs and requires a power down reset. I decided to start from scratch, uninstalling Poser 5 and reinstalling the original without the patch. The system still hangs!! My original Poser 4 still works fine through all this. I just can't get up and running on Poser 5 again. Help please, Bob Bulkley