Don't reinstall an os for some issue like this, that's insane.
First, check your mouse settings in windows (I assume you're on windows).
And make sure you don't have some setting there that is causing this.
Second, if you're using a trackpad, stop. Get a real mouse. It is likely that your trackpad is the cause of the issue.
*************** THE BELOW WILL DO NO GOOD IF YOU ARE USING A TRACKPAD THAT HAS SPECIAL ABILITIES. GET A REAL MOUSE. ***************
If you have verified that your trackpad is not the cause of the issue, continue forward.
Third, Assuming that you are using springlobby, navigate to your spring folder. This is likely on my documents/my games/spring on windows, or just ~/.spring on linux.
Delete uikeys.txt (just for the shit of it), delete the luaui folder, and delete the cache folder. Load up whatever game you're trying to run (probably ba), and see if the issue persists.
If that doesn't work
Fourth, Download BA via the itch.io client here:
https://itch.io/app
Install the itch app and then search for Balanced Annihilation within the app and install it. I give you a 99.9% chance that the issue will disappear.