I'm sorry I don't know enough about win2k to help in getting past the folder access issue. Have you tried this as the administrator (sorry if this is an XP term).
Are these services running as you mentioned previously - avast! Antivirus - avast! iAVS4 Control Service - avast! Mail Scanner - avast! Web Scanner rather than just aswUpdSv.exe avast Update ?
avast! icon missing - As a temporary measure you can create a desktop shortcut for this file C:\Program Files\Alwil Software\Avast4\ashDisp.exe (the avast icon and interface to the providers).
Have you tried a forum search for win2k and 4.7.287 or check the Beta sub forum of this forum. I can remember an issue with win2k access denied and some XP users with folder permissions.
Unlocker might be able to get rid of stubborn files/folders
http://ccollomb.free.fr/unlocker/ is also good as it also has a few additional features to not only delete the files but stop any process that is stopping you from deleting a file.