... a long time ago I downloaded a lot from the exchange that put insimenator in my game...
The evils of the Exchange.
Mods that are installed through a lot download aren't found with the original name. Instead the name will be a 32 character string of numbers and letters (a-f). The best way to help find this old version of InSim is to use Clean Installer to recursively browse your download folder. Sort by type then. Look for any and all 32 character string file names that don't have a type assigned. Hightlight them, then right click to disable them. This changes the file extension to .off so they won't be read by the game. You should be able to install InSim then.
If you want, you can later go through the .off files to see if there's anything there you want to keep, or just use Windows Explorer to delete them all.