You absolutely can uninstall SP2. It will even set a restore point for you. I would strongly recommend SP2 to everyone. Yes, it breaks some applications...that's because it is doing what it is supposed to do and enforcing security restrictions that have been...lax...in the past. Yes, that even breaks some of MS's stuff, but you can't have a system that is both more secure and 100% compatible (some of the Windows security holes are there because, until now, ensuring backwards compatibility was more important than security...that's been changing). You will probaby find that the new firewall complains when you open Poser (Poser checks for various things over the network, it appears), but that won't stop you from using it (you can set it as a "trusted" application if you like, or you can just let the firewall block it...I haven't seen any problems from this).