Testing game port on sound card, how?

I have a Yamaha DS-XG soundcard (believe the model is YMF-724), and I suspect the gameport may be malfunctioning. I have a Gravis Blackhawk Digital joystick, about two years old, which had stopped working properly. Buttons and axis' would act as if they were constantly pressed. At first I tried a new soundcard, the TB Montego II Quadzilla, but after three failed installation attempts, discovered that it wasn't compatible with my motherboard. I tried a USB joystick, but didn't find one that felt as good as my Blackhawk.

I bought a new Blackhawk Digital, and put the old soundcard back in, and happily discovered that I had a working joystick again! Or so I thought. Last night, the less than a month old stick started to misbehave. After working flawlessly for over three weeks, now the up/down axis no longer registers. Windows tells me everything is working properly. I installed the latest drivers for both my soundcard and joystick, neither of which made any improvement.

As I find it highly unlikely that two Gravis joysticks, both less than two years old, would fail, I again suspect the gameport on my sound card. Problem is, as I say, according to Windows, it's working right. Is there any way to test it? I'd really not like to get another sound card, as I really like this one and am not excited by the prospect of trying to find one that will install smoothly with no problems.

Does anyone still sell a separate game port card?

Thanks in advance! My computer can be found at:

http://www.aaroncgilbert.com/computer.html

Cheers,

Aaron