As for NAV 2005, why dont you try uninstalling and reinstalling the program: Also see this page if it helps
http://service1.symantec.com/SUPPORT...rc=bar_sch_nam
And are you sure you dont have any spyware or malware thats preventing you from updating. Please check for spyware/malware and try updating NAV 2005 via Intelligent Updater. More info on Intelligent Updater here:
http://service1.symantec.com/SUPPORT...rc=bar_sch_nam
As for DivX, thats a common problem. Make sure you dont have any background processes running and try NOT to play them in WMP, especially 9 or 10. I dont have a fix for this, but it usually looks like if you play it in the bloatware thats Windows Media Player, it inevitably stutters because of all the things WMP is doing in the background, checking for updates, downloading the latest entertainment information from the website, etc. As for encoding, try using an older version of the DivX codec., that really helps.