I have TrendMicro max security and scan regularly my pc (Samsung, windows 7 professional). For past few days, this hidden folder called !W2Sf;7R keeps appearing on my hard drives and in the My Documents folder. I did two full scans for any infection, results come back fine, no threat detected. The hidden folder has a couple of hidden files (doc and ppt with the same ! prefix). I deleted, emptied recycle bin, and did full scan after that. Few hours later, the folder appears again. Is this some kind of Trojan or virus not detected by Trend micro?