Help Downloadling MGtools

Hi I'm following the steps in the malware removal guide everything's going good except when I attempt to download MGtools to my c drive I get the following error message "you dont have permission to save in this location. contact the administrator to obtain permission".
I'm the only one who uses this pc there are no other user accounts except mine so I'm not sure what I can do next. In the removal guide it states you can download and run it from your Desktop as long as your Desktop folder is located on the same drive that you boot Windows from.
My question is how do I determine if the desktop folder is on the same drive I boot windows from? I'm thinking this may be something easy to determine but my pc knowledge is limited. Or maybe someone knows how to get around that error message I keep receiving?

Any help at all would be appreciated.

I'm running windows vista home premium

 

Thanks a lot chaslang will do!