Hey Rosh - serves you right for NWN2 bashing! :D
In all seriousness though, go to your start bar, then select run. In the textbox type in "msconfig" (without the quotes) and press enter. When the system configuration utility shows up, select diagnostic startup on the general tab so you can boot up with the minimal drivers and processes. After that try testing out your comp. If it's still struggling, then the slow-down is not attributed to background processes and application loaded within the RAM. Therefore, it would probably be best to if you were to then run your virus scanner (Norton or McAffee work great) to dig out those potentially nasty worms, trojans and whatnot. If that fails (i.e. no virus is found), go to your start bar-->accessories-->system tools-->system restore. Select an earlier date (one when you know it was working fine) and roll it back. If after this it's still slower than Troika when releasing patches, then you're going to have to re-install Windows to factory settings, so look out for your system discs (or recovery partition).