It's possible to use a remote connection to repair a computer....it depends on the access you have when connected for what you can see and do (what is shared).
It's also possible for a hacker or malicious user to do a great deal of harm using remote access....
When you are connected remotely, you see the desktop as it would appear to the user, and you use your mouse as if the desktop was yours, etc.
I would think the teacher set things so you could share the file on the desktop.
There are free remote utilities you can set up and try at home:
Some are trial versions that expire or are limited
https://secure.logmein.com/home.asp?lang=en http://www.bestfreewaredownload.com/...-wxkextjn.html
If the host PC is using Windows XP Professional:
http://articles.techrepublic.com.com...1-6119547.html
There are other utilities which will no doubt get posted....