You might want to take a quick look at Glary Utilities
. It has a free version as well as a paid for Pro version. I'm using Pro but had a quick look at their website for the free version and the things I mention below appear to be in there.
Firstly, this is a tremendous free application for general PC maintenance - it has a simple one click option for undertaking automated routine clean up. I've been using it for years and it helps keeps my PC's free from clutter both at the file and registry level.
With respect to your specific q's - I think it will do what you want but not in the way you envisage - actually I think it might be better for you, if I understand your requirements correctly:
Under the Modules / Files and Folders section is a Disk Analysis option. This performs a summary analysis by folder, disk or multiple disks
depending on the search / scan critieria you select. The explorer like interface then visualises:-
1) Which folders are using the most / least space
2) A summary of each file type i.e the total size of each file type by folder / disk(s). So for example on my PC right now I can see that I have 1.13GB of .jpg files on my C drive in 17234 files! (they are mostly small web design image / icons)
3) By clicking/selecting on the file type a sub pane in the interface lists all of those files (and if you initially analysed multiple disks then it would present them across all disks). I can order the files my name, location, size etc in the usual Explorer way.
4) The appllication also includes an inherent link to Windows Explorer - so once you have identified the appropriate file you can easily delete / rename etc. without having to leave the main app or rescan.
I think this might be better as with this approach you get "live" files update as you scan. With the excel approach everytime you added / delete files you would need to manually search and copy / paste update Excel. Then you would need to do what you wantedneeded to do in Excel and then manually locate the file you wanted to make changes on in Windows Explorer which is pretty tiresome and labour intensive.
Incidentally, another module included in the main utility app is a duplicate files finder. I've not had the need to play with that yet but that might also help you out.
Hope this makes sense, it's a bit difficult describing the functionality exactly but I suggest you give it a try as it's free, it is pretty simple and intuative to use and even if it doesn't solve the problem you mention (but I think it does, as I use it in a similar way to control my mp3 files), it's still a fantastic clean up utility.