I just had a strange problem recently, one of our customers brought a Windows 7 computer to us and told us that the keyboard and mouse didn’t work. I plugged in a wired keyboard and mouse and it worked fine, but when I plugged in a wireless keyboard and mouse it did not work. Sometimes it would recognize I plugged the wireless usb receiver in and other times it wouldn’t, when it did recognize the wireless receiver it would install a driver and then you had to restart. Once I restarted, it would still not recognize the keyboard and mouse. I searched online on a bunch of forums and tried there tips, but nothing helped.
I tried different usb ports, updated the bios, took out the cmos battery to reset the bios, went into bios to make sure usb was enabled, and tried the keyboard and mouse on another computer. I also could use the wireless keyboard in the bios but not Windows 7. I tried using the keyboard in safe mode and that to didn’t work. I also updated the chipset and graphics drivers to no avail.  I went into Device Manager and found that the PCI Simple Communications Driver was missing. This computer was a custom built computer so I found the motherboard model (DG33TL) and installed the Intel Management Engine Driver from Intel.  I then installed Microsoft Mouse and Keyboard software and Microsoft Mouse Intellipoint software. The computer still didn’t recognize my Microsoft desktop 800 keyboard and mouse, so I plugged in my wireless usb receiver for a Microsoft keyboard 5000 and Windows and the Microsoft Mouse and Keyboard software both recognized it. I then unplugged the Desktop 800 wireless usb receiver from the computer and plugged it back it in. Windows then recognized the device and installed the driver. I restarted the computer and everything worked fine.

That was what worked for me. Let me know if this works for you by posting in the comments section.

I hope this helps. This was posted by techspeeder.