Here are some things you can try with increasing severity...
1) Go into network connections, find your wireless network connection icon, right-click it and disable it. Re-enable it and see if any improvement
2) as above, but reboot after disabling, and once your computer comes back on, re-enable.
3) Go into Device Manager, find your wireless network adapter, uninstall it, and reboot the computer. Your PC should detect it and hopefully automatically install it again.