I have used TDSS Killer in the past and note when adding the loaded modules feature it would reboot the PC and, begin running immediately on start-up.
After a recent Java 7 update 21 the PC started acting strangely (slow internet speed etc.). I threw the preferrable chemical cocktail at it, I know how you guys like that (including combofix...) and now, when I run TDSS Killer (or FixTDSS Symantec) I get - along with the TDSS Killer Run Box - a System32\cmd.exe pop up on reboot.
If I click on the Run TDSS box, the cmd prompt box also closes and the TDSS Killer runs with no suspicious objects found.
If I hit "any key" (to close the cmd prompt pop up) "access denied" very quickly appears in the pop up and the cmd prompt box and the run TDSS box both close - although TDSS Killer does not run.
I should add Rogue Killer previously detected Zero Access infection a year or so ago (although thought disinfection was complete).
Windows XP SP3 with McAfee AV Seciurity and Malewarebytes Pro. No infections detected.