Applications getting stuck during installation

There have been several applications which I have tried to install where the installer just got stuck. This includes Windows Live Messenger which dies when using the defaults (installs more or less everything additional). Adobe Flash CS3 installer also froze my PC a few times and the application dies on startup. Dreamweaver doesn't close down properly, it always remains running as a process. Unless that process is killed, it will not become visible again. Windows also gets stuck during shutdown for some odd reason after already closing all running applications before doing the shutdown.