Win7 is an improvement over Vista, yet at the same time they dumb everything down so an 8 year old could use the computer. Sigh, it won't even tell you anything these days. UAC says oftentimes:
origin: downloaded from the internet
or
origin: a hard drive on this computer
WOW THAT'S SO DESCRIPTIVE! It doesn't even tell me what hard drive it is! THANK YOU WINDOWS YOU'RE SO HELPFUL
/rant
another way to do this is to right click --> properties, it should tell you what kind of file it is.
oh, also, a single left click SHOULD tell you what it is in the bottom left of windows explorer. It probably won't though for anything outside basic stuff like "text document"