Accidentally deleted standard PS/2 mouse driver, want to restore it  

I was playing a 3D shooter video game, when I noticed my mouse was behaving in an odd way like never before. If I moved it fast enough, suddenly the first person camera of my character (the cursor) would stop moving, and instead my system would fire a single mousewheel scrolldown. I don't know if it was the game being glitchy, but after noticing this behaviour I tried to clean the bottom of my mouse and press the mousewheel several times, it didn't fix anything. Instead it did the exact opposite of it; my mouse completely stopped moving on the screen. The lights indicating that the mouse is plugged in were still on, and if I moved the mouse the lights would become stronger indicating movement, but the pointer didn't move on the screen. I plugged it in and out several times, but to no avail. I had no idea what happened but I was sure it's not the problem with the mouse since it was working (the lights). (I had another mouse to try if it works but at this point I didn't. I'll mention that mouse later.). Eventually I went into the Device Manager, and under "Mice and other pointing devices" I right-clicked on "Standard PS/2 Mouse", then Properties, then under the Driver tab I clicked Uninstall for the reason I've read that my system would reinstall it after I reboot it. It didn't. And now I have no hope what to do, I have tried to somehow reinstall all drivers, I tried an other mouse too, didn't work, I tried to get back the driver in all the ways possible but it seems I can only get it back if I completely reinstall my Windows 7, which I don't want. On the picture below you can see how the "Mice and and other pointing devices" is completely missing now.
If you didn't read the whole text, the thing you have to know: I uninstalled my PS/2 mouse driver in the Device Manager under "Mouse and other pointing devices", and the latter can't be seen anymore on the Device Manager, nor the PS/2, as presented on the picture. I just want to restore/reset/get back/reinstall the driver, and maybe get another mouse that's going to work properly. Note that I do not want to reinstall my OS. Thanks in advance.

InteLStaT

I see you didn't delete USB controller from dev. mgr. Does your PC have usb port? Maybe borrow a usb mouse from a friend or buy one, might work. Sounds like your PS/2 mouse itself was failing and it needed replacement.

edit-you stated " I tried an other mouse too, didn't work," you didn't say what type it was :)

I do have USB ports, but I don't have USB mouses and in my area everyone mostly uses PS/2 mouses because they are the only thing sold... the other mouse I tried was PS/2 too, and it was the exact same model from the exact same manufacturer, I knew it worked because I have used it in the past. Tried both of the mouses on an other computer and they worked fine, but they didn't on the problematic computer.
EDIT: Right now I'm using the Ease of Access numpad mouse control.

Yes, I did, and I meant that after running sfc /scannow for the first time, and then rebooting, the non-genuine message appeared in the bottom right of my screen. My Windows was genuine before. In the Properties of Computer, it acts like it's completely unactivated, and asks for the product key, which I have already entered when I bought my computer. To this day I forgot the product key sadly, and trying to open the activation dialog from the Properties just gives me this error:

C:\Windows\system32\slui.exe
Windows cannot access the specified device, path, or file. You may not have the appropriate permissions to access the item.