Loose Rivets:
I personally would never have allowed anyone from Google near my computers, let alone taking control of them. (Then again, I only use Macs and other Apple products but, I digress.)
I don't know what operating system you use on the PC in question but if it is Windows then I would strongly suggest that you reboot that system in "safe mode" and then fall back to the "last known state" or whatever it's called.
This way, if anything nefarious was performed by the Google employee will no longer be in the OS. Strongly, strongly suggest you do so Loose.