David.
g2mcomm.exe is a component of Citrix GoToMeeting application. It seem from your post that, some of the applications files are corrupt.
Citrix GoToMeeting
http://www.citrix.com/products/gotomeeting.html
I would suggest you uninstall and reinstall the application, the refer to the link below, for troubleshooting tips and instructions on how to configure the application correctly.
Running chkdsk as already suggested to verify that there are no corrupt sectors on your hard disk, is a good idea.