Since this seems to of some urgency, and diagnosing some problems can take awhile, I'd go ahead and buy a cheap $15 wired mouse and give that a try first. Get your work done, (if possible) then
tackle the problem.
If you've installed or updated/patched the OS, any programs, or any drivers recently that could also cause problems.
Rolling back to a restore point to the day prior to the update/install could eliminate the problem. Restore points are automatically created when most updates/installs are performed. However, backtracking to a prior restore point can cause other issues, so you should search for and read up on "restore point" and "side-effects" or permutations of related words before you do.
I'd also make a FULL system backup before doing anything
. I highly recommend either freeware Macrium Backup Free Edition, or DriveImage XML. I consider them very high-quality, safe, and reliable programs, and numerous tutorials (even videos) exist if there is any question how to do something using either backup tool. I consider either one far superior to Microsoft's backup program, although I personally prefer Macrium Reflect Free Edition.
With a full backup if you make a change and it causes more problems than it fixes, you can always return to your exact current state within minutes without any problem.
I have no personal or financial interest in either program mentioned above.