Once in device Manger Look for Network Adapters to the left of network adapters click on the arrow to expand the list of adapters, in the list look for your Realtek RTL8191SE Wireless LAN 802.11n PCI-E NIC Right click on it and choose Uninstall. Now reboot the computer, windows will reinstall the adapter for you.
Use the computer for a while and see if any change results.
Thanks
Joe