The only work around i found is to disable the wifi interface, wait 5-10 seconds and re-enable the interface.
By doing it this way you don't have to reboot your system.
Do not try to turn off wifi and turn it back on via the laptop buttons, that is not the same as disabling it and re-enabling it.
Steps for Win8.1, but i think it's the same for Win7
1. Right click on your wifi icon and select "Open Network and sharing center", or in Control Panel select network and Select "Open Network and sharing center"
2. Select "Change adapter Settings"
3. Right click on your Wifi Adapter (which is probably stuck at acquiring I.P.) and select "Disable"
4. Wait 5-10 seconds and the right click on the adapter again and select "Enable"
5. Wait a few more seconds and you should connect to your router.
You can keep this last window open in the background minimized so you don;t have to go through steps 1 and 2 every time.
Again this is only a work around so you don't have to reboot every time.