I just upgraded to Windows 8.1 Pro because I want an additional layer of security in case my laptop (and research) gets stolen. Didn't knew about the TPM, and seems I don't have it (I have an ASUS N550JV). So for what I read I need an USB pen drive plugged into the computer EVERY time it starts up. I can deal with that. Question is: after the computer starts, can I safely remove the USB drive, or does it need to be all the time there, consuming an USB port? Thanks for the help.