I just wanted to add my answer to this question. Same thing happened on my Dell Dimension E521 using MS Vista 32-bit with yellow ! on the PCI Input Device.

I just have to select it from the device manager right click and click on Update Driver Software...

Select on Browse my computer for driver software.

Select on Let me pick from a list of device drivers on my computer.

Select Sound, video and game controllers.

Click Next.

Select Generic for the Manufacturer.

Select Unsupported Standard Game Port.

Click Next.

Click Yes.

Click Close.