I believe from your explanation you may have only removed shortcuts to the application, and the source files still remain.
Method 1 - Windows
On Control Panel, go to Uninstall a Program and ensure there is no entry for TOR. If there is, uninstall from there.
1.Click the search bar at the bottom right of the screen
2.Type Control Panel and click the obvious result
3.Locate "Uninstall a program" and click that
4.In the search bar, search "Tor"
5.If it appears, then remove it.
Method 2 - Revo
Download a program such as REVO Uninstaller then locate the program there, and click uninstall. This is a more thorough method of removing files than windows built in.
Method 3 - Manual File Search
A few probable file locations to check is the following:
2.C:\Program Files (x86)
3.C:\Users\[Current User]\AppData *(YOU MAY NEED TO ENABLE HIDDEN FILES ON WINDOWS EXPLORER, VIEW TAB)*
You say that when you try to open FireFox, Tor comes up?
You could try right clicking the part you click to open FireFox, checking the properties and see if the link leads to TOR.
On windows settings, in the search bar type "Default" and click "Choose default web browser". Check what the default app is in there.
If you did not accidentally/purposely set TOR as default browser, then your system could be compromised by a Virus. In which case run a few Virus scans and check.