most routers have a setting within them by which the total number of local area network IP addresses can be limited.
If yours has been set to 2 then trying to connect a third pc will fail.
To test this try switching off one of the 2 working PCs and then try to connect your notebook.
Unfortunately this is not the only way in which the router could have been configured so as to cause this effect and without knowing the find detail it is difficult to suggest a cure but $99.95 does seem excessive for what would be a fairly simple adjustment. Surely there is some enthusiastic geek available in your area that could fix this.
I just bought a new HP notebook, and when I type in the passcode it says that I may have mistyped the passcode. This is not the case, I have two other computers working on the router, and I even generated a new passcode and reset the other two computers and they connect fine. HP directs me to Netgear support, and they are trying to tell me that the notebook is a "different platform" than a regular desktop or laptop, and I need to pay them $99.95 to change some settings in my router to make it work. Can anyone tell me what I would need to change?