a.exe is a file that cannot be deleted, plus it is blocking all attempts to run spybot SD.
Hello edmixon,
This is the malware removal forum and the procedure is here:
"BEFORE you POST"(READ this Procedure BEFORE Requesting Assistance) (http://forums.spybot.info/showthread.php?t=288)
If you can produce a HJT log please start a new topic.
Questions regarding Spybot-S&D support can be asked here: Spybot-S&D Forums (http://forums.spybot.info/forumdisplay.php?f=4)
Regards. :)