When you reformatted and reinstalled:

You loaded chipset drivers right?

You loaded sound drivers?

Video drivers?

WiFI?

LAN?

You don't just reload windows and update. If you didn't go through and reload all your drivers then of course the hardware won't work. Some stuff like sound and video will work off the default drivers your OS has, BUT will be very slow until you actually load the current drivers you need. Chipset drivers, you may not notice one way or the other if you don't laod em, but...maybe some of the hardware built into the mobo will not function as well if at all if these are not loaded.

Right click "My Computer" icon.

Choose "properties"

Choose "Device Manager"

Do you have any yellow question marks?