|You often can't see any physical indications of damage. It only takes a tiny extra amount of amperage (current) to damage the circuits connected to the port. |
By the way, devices plugged into PS/2 ports are NOT "hot swappable" - they should only be plugged in or unplugged when the computer is not running, otherwise you can damage the circuits connected to them and/or the PS/2 connected device.
I know of no diagnostic program that can test a PS/2 mouse or PS/2 keyboard port and/or it's circuits that isn't working.
A PS/2 mouse or PS/2 keyboard port and circuits connected to it either works or it doesn't. The default in most bioses is the PS/2 mouse support is enabled or Auto, and when it is and a PS/2 mouse is connected, only a PS/2 mouse can use it's mandated IRQ 12, so another device using that IRQ is impossible, and it's extremely unlikely another device would use the same I/O address it requires, so you can pretty well always rule out a hardware resource conflict disabling a PS/2 mouse (or PS/2 keyboard).
It's a very good idea to use a device or devices that protect the things I mentioned from power spikes and surges - e.g there are power bars and UPSs that have that. However, a lightning strike on your AC power grid or close to your location can damage anything in spite of that. Better such devices come with insurance against damage that you can make a claim on, even in the case of lightning damage.
A USB or serial mouse should work fine.
However, a USB mouse may not be detected and usable the first yime you connect it until just before the Windows desktop has loaded. That's no problem if the computer has only one user and login is automatic because no password was used for the user, but if there is more than one user, or if a single user has to type a password while booting, you can use the Tab key on your keyboard to toggle to select the active selection if it isn't right (it has fine dots around it or is highlighted) and your Enter key and possibily the cursor keys to do what you need to do while booting.