TeamViewer is a remote desktop sharing utility useful for accessing another computer remotely. It can be run standalone or by installation, but I prefer running it standalone without installing anything into my system.

You can browse and download the files from the other computer and also upload. You can also do voice chatting. You can use it to solve the issues of your friend’s computer.

Full list of features can be found here: http://www.teamviewer.com/hi/products/benefits.aspx

It is available in free version, which you can download here: http://www.teamviewer.com