My keyboard and mouse on my new build works in boot up, but once it logs me in, it stops working. I tried getting a new mouse and keyboard, moving the USB Connector to the back, and tons of other things. They are all wireless, but I did try using a wired one. I am able to get a new OS, would that fix it? I checked the connections in the computer, and they are all good as I thought, because if they were not the mouse and keyboard wouldn't work on boot up. Anyway, I CAN get a new Windows 7, anybody know if that would fix it? Thank you a ton, I spent about $1400-$1600 on this build, and I really need this fixed. I am willing to pay $2 PayPal for a good explained answer !
Can the offers of money mate, we help because we can.
My first suspicion is that you're using wireless devices that'll need drivers to work under the OS. But you say you tried with a wired device too, are you plugging the keyboard into a USB 3.0 socket, that will cause many to stop working (don't ask why, but they seem to hate it, my Corsair K90 and Saitek Eclipse 2 both refuse to work under Windows if plugged into the USB 3 socket).
Have you made sure to install all the motherboard drivers, as many will have a separate driver for the USB sockets (which on some motherboards can come from two different providers, requiring two different drivers). Also if your mouse and keyboard require drivers, make sure those are installed too.
Of course, without knowing more about your system (motherboard and keyboard/mouse specifically) I can't say much more than that.