Windows XP, unable to run MBAM or ComboFix

I have a Windows XP Pro SP3 computer that was unable to open Quickbooks, so I tried updating and running MBAM. MBAM opens, but evenutally hangs. I ran TDSSKiller, and it found 1 rootkit and removed it on reboot (I didn't pay attention to the name of what it found). Still cannot run MBAM, so I ran ComboFix. I know it's not advised to run ComboFix without supervision, but I've had pretty good results in the past. At any rate, Combofix starts, extracts files, backs up the hive files, then nothing. Task Manager shows that cmd.3xe is running, but no CPU usage, and the blue CLI window never opens. No other "3xe" files or anything else I would identify as part of ComboFix are running. I suspect there is still a rootkit, but I don't know what to do to remove it at this point. My host file looks normal. I also ran HijackThis and didn't see anything out of the ordinary. Any help would be outstanding.

via Bleeping Computer Last 20 Posts http://www.bleepingcomputer.com/forums/t/509086/windows-xp-unable-to-run-mbam-or-combofix/