I installed TweakVista just for a quick fiddle but I like to keep my PC with as little software on it as possible so I uninstalled it when I lost interest but all my animations, like you get when you minimise and close stuff, have all gone. I've been looking through the registry and I've reboot DWM and my computer and all I can think of. I hadn't changed anything when I uninstalled it but desktop composition still seems to be working because the Start + Tab thing for Flip 3D still works.