Okay,sorry to hear the reinstall didn't work.
Since you've tried just about everything,would you like to get checked out in the malware removal forum,just in case it's something hidden?
They don't ordinarily do checkups in there,but Spybot is a security program,and it's not being able to run could possibly be due to some sort of malware,so it should be okay for you to post in there. :)
There are instructions here:
http://forums.spybot.info/showthread.php?t=288
Malware Removal:
http://forums.spybot.info/forumdisplay.php?f=22
You could also add a link to this thread in your post.
If you do go to malware removal,and nothing is found,once you are all done there and your thread is closed,then you can come back here,and we can see if we can think of anything else to try.