1. Have you re-installed all your drivers as well.
2. I take it you are trying to connect to a router which is already configured previously.
3. If you have an internal wireless network interface card make you install the drivers for that and same goes if it is a usb wireless adapter.
4. Install third party wireless connection software if provided, else ensure the windows zero configuration (wzc) service is enabled and then use the monitor bottom right hand side of screen right click and choose wireless connections and click on your connection enter network security key when prompted.