Your last resort is reinstalling the system software. There are two options:
1. Archive & install leaves all the other files on your computer and only re-installs the software. But you need to back up, just in case. Afterwards, if everything went well, get rid of the folder called that contains the old system files, as it takes away considerable disc space (not sure what it's called, something like "old system"... something with "old".
2. Complete new install, where you wipe the disc, re-install the system software, and all your other software, and then drag all your files back to your hard disc from your back-up. For this two back-ups are recommended, as you never want only one copy of your files (which you will have for the two hours you need wipe and re-install your software). This is probable the better option, as it would take care of any hidden damage in any of your software packages. Just don't forget to deactivate any Adobe software before you wipe it out.
In any case, this should take care of the problem, and I guess it's a better solution than forever guessing where the error might lie.