I have a Thinkpad X30 laptop with three mouse buttons below the keyboard. Unfortunately, the middle button doesn't actually function as a middle-click, instead, it has some sort of confusing scroll function that worked with the trackpoint and I could never get to figure out. Any idea as to how I can get normal middle-click functionality working on Windows XP with this button?
Note: I read the answer by scoop, but then looked at the specs for the x30. It seems to indicate that the x30 uses ultranav. I have a t61p, and the below works with my ultranav. Worth a try:
Go to Control Panel, Mouse, and click on the UltraNav tab (it may be labeled TrackPoint instead).
In the TrackPoint section, click on the Settings button.
This will bring up the TrackPoint Properties screen.
In the "Choose Scrolling or Magnifying Glass Function" section, pick the Neither option.
Neither probably should be labeled "Middle Mouse Click", but it's not.
I personally use the scroll feature, which is the default. It takes a couple days to get used to it, but it provides better control over scrolling than the trackpad. To use it, click and hold it with your thumb (your cursor will change to scroll bars), then use your index finger on the trackpoint to scroll up/down. After a couple days your thumb will naturally find the 'lip' of the middle button.
With this little program called TPMiddle you can use the trackpoint for scrolling AND middle-click at the same time:
I use it in the Thinkpad W530 and works very well, might work for the Thinkpad X30 as well.
You can fix this in the registry by editing the key:
Change "TrackPointMode" to Hex value
This makes the middle mouse button of the TrackPoint behave as a normal middle mouse button instead of activating the scroll function. You can still click-and-hold to scroll if you want to.
This works even if the UltraNav settings don't give you the options shown in @WireGuy's answer and has been confirmed to work in Windows 8 and Windows 10.
Before anyone claims this to be a Ultranav touchpad again, I explicitly states that this is a Synaptics OEM touchpad, and should work with a Synaptics touchpad driver. (Which works on my X31 too). If you install enough Linux on Thinkpads, you'll realize most of them uses Synaptics Touchpads.
Okay - go find a Synaptics touchpad driver - maybe refer to this SuperUser.com thread here, install it, and give it a whirl.