So here's a new one, for me at least. My mouse will not work in GTA IV. It works fine everywhere else, other games and all, but will not work in GTA IV. I can't move it in the opening menu, in game, or in the pause menu. The mouse for GFWL works after pressing home since it is just the normal Windows cursor. I tried running the game in windowed mode, disabling my second monitor, unplugging and plugging in the mouse, even restarting the computer with no luck. It just started happening out of nowhere. No new mods since the last time it worked, or any other changes to the game, or even any computer hardware. I really don't want to have to reinstall the game, so I was hoping to get an alternate solution here.

 

Edit: It does work in the LCPDFR computer.

 

Edit 2: The mouse buttons do not work, either. I cannot scroll through weapons with the scroll wheel, aim, or shoot. However, I have the airhorn in ELS mapped to the right mouse button, and that works fine. Only the default GTA IV functions are not working at all.

Edited May 29, 201411 yr by willpv23

Same issue here, I tried my backup copy (which was working perfectly about 24 hours ago) and that doesn't work either. The only thing I've done since then that may have affected it was updating Watch Dogs.  

Same issue here, I tried my backup copy (which was working perfectly about 24 hours ago) and that doesn't work either. The only thing I've done since then that may have affected it was updating Watch Dogs.  

 

I also installed Watch_Dogs...Could one game break another...?

 

Edit: Apparently so. Verifying the files for Watch Dogs fixed the issue in GTA. Makes sense...

Edited May 29, 201411 yr by willpv23

Try deleting your savegame files from appdata/rockstar games/gta iv (IIRC) and from my documents - it could be some sort of setting disabling the mouse.