After computer recovery - browser speed slow, internet speedtest normal

Hi, My friend did a windows recovery after he had a black screen when starting windows. Both IE and Firefox had slow connectivity yet I had him do a speedtest with speakeasy.net and it showed good speeds. He says the longer the computer is on, the slower is a surfing the internet. CPU usage is normal.

internet speeds:
2500kbps/400kbps

Could the recovery have messed with his computer networking drivers? He used a gateway recovery disk. His computer is either a gateway or dell computer.