On all my systems (xp, Win 7, Win 8 latest one)
Same process..
Install opcom, then go to opcom directory in program files, there will be a folder called drivers to check... You need to go into the device manager and right click the device, update driver and point it to the opcom driver directory and click next etc.
Should install then..
If not... download http://download.teamviewer.com/download/TeamViewer_Host_Setup.exe
then install and give me the ID and password.. I can then connect over and set it up for you.