Ad-aware, Microsoft antispyware, CCleaner, and whatever flavor of A/V you use. Best bet is to reformat and install these programs on a clean system instead of hoping it still functions after being adware/virus laden for unknown amounts of time.
BTW uninstalling NAV2k5 is a three hour ordeal involving regedits, reboots, safemode and registry cleaners if the uninstaller doesnt like you.