I just cleaned a client's computer that had Tenga- his came through a remote attack where the attacker was trying to run a CounterStrike server off the machine. Anyhow, Avast started automatically moving infected files to quarantine which was not ideal. Tried a boot-time scan but all it could do was delete files as none of them could be dis-infected. Thankfully, after the 3rd file, I quit the scan and booted back into safe mode.
I found Avast's Aswclnr.exe which is a cleaner specifically for Tenga. Over 2900 files were infected, pretty much every exe on the PC whether it had been run or not. The cleaner managed to dis-infect all but a couple exe files.
Note- during this, I had to turn Avast off 'permanently' so I didn't lose any more files to quarantine. After the first run of Aswclnr.exe, I then restored the files that Avast had quarantined and ran the tool again to clean those.
Highly recommend you get this tool and use it- nothing else I tried would clean the files, they all just wanted to delete. You do NOT want to clean up that mess!