Open device manager (right click my computer,go to propeties,hardware,device manager),open the computer tab (first one down),Double click on "Advanced configuration and power interface" (to get to proporties)click the drive tab,and go down to "update driver",once you get there choose "next",then "display a list of known drivers for this device so that I can choose a specific driver" click next,then show all hardware for this device class,then you will see a list of drivers, you want:
Manufacturer=standard computer Models=standard pc
Install this driver (it will say it wont work but it will) Reboot after you install this (it will ask you to reboot).
When you restart it will load all your devices again,you may need to track down certain files and drivers using the "find files or folders" tool ,once it reloads all your drivers you will reboot and then everything will be ok.