Just out of interest, did you delete the partition, recreate it then format the C drive? If you only formatted C then it is possible that something survived the format.
When you re-install make sure the PC is disconnected from your network and the internet, re-install, put in all the drivers you need then install a firewall and Anti-virus/spyware software. Once you've done this, connect back to the internet and get all the normal updates for everything.
If this doesn't sort you out then I'm sorry I have no idea what is causing your problem there!