OK, I am going to try to remove TrustedInstaller from my system and see if I can reinstall it. It may turn out you have to do a REPAIR install to get it back, but I will get back in a few hours. Until them, try right clicking the file and see if a "Restore Previous" option is available. If you have the file in the correct place, it might work. Of course, it might need the TrustedInstaller for it to work..... Did the TrustedInstaller file show normal size after you copied it to another location, if that what you did, before moving it to the other computer?