The only way to erase all evidence of the browser bundle is to write random data over the entire hard drive. Here are the traces that TBB leaves behind on Windows after you delete the folders it was extracted to: http://dkn255hz262ypmii.onion/index.php?topic=148291.msg1152452#msg1152452 That's what we know about based on one analysis. There may be other traces on other setups. Check if your hard drive has the ATA Secure Erase feature and use that to perform a full disk wipe. If it doesn't have that feature, download DBAN and use that to perform at least one random write over the whole drive. Then reinstall Windows. It will still be obvious that you reinstalled Windows.