Hi, recently my friend borrowed my portable hard drive, and when i plugged it in i scanned it with avast! but no virus were detected. An hour later, I was working on my thesis, and I saved it in my computer. but when i looked in that folder my thesis wasn’t there! :o The same thing happened to my friend’s computer, files were moving from one folder to another. 
I tried boot scan with avast! but it still did not detect anything. Please help! thanks! 
download malwarebytes anti- malware update it and do a full scan if that doesnt work download hitman pro update it and scan it…do attach logs on next comment…