Yesterday's patch release for GTA IV's PC version brought new problems for some users, such as a stuck key/input issue that leaves your head spinning. For real. Rockstar's suggested a fix.
Rockstar's forums are GTA Forums is alive with complaints of unresolved bugs, even new ones, so if you're seeing the same kinds of things, you're probably not alone. However, the look/spin issue is the only one Rockstar's commenting on so far. Here's the word, as of 6:45 a.m. today.
With the latest Title Update, some users are experiencing a Look/Spin/Stuck Key issue that interferes with user input. The temporary fix, described below, will restore Keyboard/Mouse and XInput (360) controller functionality. Support for DirectInput devices is currently limited. We apologise for the inconvenience and appreciate your patience.
To fix the issue:
A1) Unplug any DirectInput controllers (gamepads, joysticks etc..)
A2) Reboot your computer
A3) Launch GTA IV
If the issue persists, the following instructions are provided as a guide to assist you in deleting the conflicting DirectInput drivers:
B1) Exit game
B2) Go to Start->Control Panel->System->Hardware Tab->Device Manager->Human Interface Devices
B3) Locate drivers for devices
B4) Delete drivers for devices
B5) Launch GTA IV
**Some users are able to reinstall the drivers for their DirectInput devices, with the device attached, and have found that it will work in game. If you do attempt to reinstall your device and the problem resurfaces, please follow steps B1-B5 again.
Edit: This is on GTA Forums, a fansite with no official connection to Rockstar, except that Rockstar's people seem to be providing support through it.
Look/Spin/Stuck Key Issue [GTAForums]