I would venture there are several things you might try, here are some ideas
[use with caution]:
1. Apply your full backup system image to the computer, making it like
shiney new.
or
2. Use System Restore to put the system back to a Restore Point from before
the installation of the updates.
or
3. Remove the installed updates manually through the Programs applet in the
Control Panel - you may have to use 'Classic View' to see it.
also
4. If "Data Execution Prevention" is ON, except the Ad32l.exe executable.
and or
5. Try running the program in Compatibility mode.
Hm
Surely there must be an AutoCAD newsgroup or forum for dealing with AutoCAD
issues? You might try investigate at one of those forums if this one doesn't
come up with the answer.
Oh, and now is the time to make sure all documents and important files are
backed up to a place off the computer (network store or CD/DVD-R discs etc.)
if they are not already. If anything goes belly-up, you will be glad to have
at least these backed up.
Saucy