Windows 7: Unable to remove old program and thus can not install new program Help

Hello to all,
Hoping someone can assist. I have been using a program called Raw Therapee. I downloaded a new version and on installing it quit saying the old version must be removed. I could not find it listed in Revo Unistaller Pro, so I did a forced uninstall with the location of the main executable. This removed a lot of stuff. I checked the program folder and the folder and many files were still there, so I deleted them. I did a CCleaner in between and after. I then unhide and show system files and deleted the folders in the Appdata of main user and admin account, couldn't find it anywhere else.
CCleaner again and reboot. Went to install the new version again and it claimed that the old version was still installed. I did a search for *aw The* and found an entry in the hidden Program Data Folder. In the Admin account it will not let me in this folder to delete any remnants of the old version of Raw Therapee. Is there some way of fixing this??? Thanks for any assistance!
Glenn

If you right click on it, in the drop down menu, is there a choice to "run as Administrator"? If so, click on that, then delete the item.

Hello Jacee,
Here is the current situation. With the hidden files unhide I did get into the Program Data\Microsoft\Windows\Startup folder where I found an entry. I deleted it. Now when I do a search on the computer, all I can find with *aw Thera* for Raw Therapee is the downloaded install program that will not install. Other than that there are no files or folders I can find. I went into AppData already deleted any entries, found some more in Local Store and deleted them. I am literally clueless. Thanks and please continue!!!
Glenn

There is likely a (some) registry entry (ies) left over. You could search with something like jv16 Power Tools, but I hesitate to recommend anyone to remove registry entries manually. A Guy

Howdy A Guy,
Luckily, another thing I didn't know was that an .msi file doesn't have to be installed, it can be unpacked and copied. Using this method I now have the newest version installed and running. Got this from the Raw Therapee Forum. Very nice people!
I also, not understanding some of the previous answers, didn't realize that I wasn't running Revo Pro in the Admin mode so it wasn't showing me the installed product, or what was left of it. Why would certain programs be hidden?? Never ran into the problem before. Anyway I let Revo have a go at it and it said it uninstalled something.
My brain must be clogged. There is to much to know IMHO about this stuff and to be competent, you must devote a fair amount of time and interest, or have a good place to go with knowledgeable friends {:-))!
Thank all who have responded with useful suggestions! You give me the confidence that somebody got my back.
Glenn

Glad you got it figured out

A Guy