TROJAN HORSE NOT BEING DETECTED? WHAT TO DO?

[Georgieee]

Hey
So about 2 weeks ago I was on Tumblr, and the Moneypak Met. Police Virus Page thing came up asking me to pay £100 so I knew it was a virus, I deleted my blog instantly. I system restored my laptop, did a virus scan with AVG and the trojan was moved to the vault.I then did regular whole computer scans with AVG and did some recently with malwarebytes, and nothing was detected. I thought that my laptop was fine because of this.
However, tonight, I can't remember what page it was, but SSL Security Certificate perhaps? Something about the websites security certificate not being recognised OR that I was under attack by hackers? SO, this lead me to believe that perhaps my laptop still had a trojan or something so I went into safe mode and did a quick scan with malware bytes, and nothing was detected. HOWEVER, with AVG, pretty much every single file is coming up as "Locked File. Not tested.". Just now a notification came up "AVG Command Line Scanning Utility has stopped working." I honestly don't know what to do, I recently purchased items online on that computer and don't want my bank details or personal details (Facebook) to be known. I don't know what to do? How do I get rid of it?
Please help me.