I'm having the same exact problem. I removed all malware using MalwareByte's, Microsoft Security Essentials, Superantispyware, and HijackThis but it won't allow me to run ComboFix even if I rename it to something completely different. This has to be a software issue as I've tried using a USB NIC and it gives the same error, about 2 seconds after the machine connects to the internet. I was able to update MBAM before the 1 minute was up which allowed me to do a full removal and I used Microsoft Security Essentials with the standalone definition updater for local virus definition updates so I know it's clean now, it's just a matter of repairing the damage caused by the malware. Any help would be greatly appreciated, I've checked services and running processes and ActiveX and even did an sfc /scannow but nothing seems to resolve this issue. Reinstalling is not an option.