Please use the new version 3 Control Panel by double clicking on xampp-control-3-beta.exe found in the xampp folder.
Right click on it and select to run as administrator if you are not logged in to Win7 as a full administrator.
You can also right click on the file and create a shortcut to your desktop or any where that is handy for you.
You will find it has much more than the xampp-Shell
If you would like the latest much improved now bug free version then please download from here:viewtopic.php?p=186862#p186862
and use it instead.