autorun disables, cannot re-enable properly

[Panda Man]

Ok, something's up with all of my optical drives, both physical and virtual. Whenever i pop a cd in/mount one, autorun won't start, even though i have both autorun/autoplay enabled within the registry. Also, the icon will not show up. However, when i do click on the cd, autorun will run half of the time. When it doesn't run, i will either get an error message about the autorun not being a valid win32 application, or i will get a "open with" prompt. When i get the "open with" prompt, i usually right click, explore, and manually select either autorun or setup, both of which give me the "__________ is not a valid win32 application" error message. So im pretty confused as to where i should go to next. After a process of elimination, i THINK i have a few .dll's that are unregesitered, but i have no clue which ones. Any help would be much appreciated! (specs in sig, winxp pro)