I would suggest you to update the BIOS and then uninstall and reinstall the Wireless card driver on the system. Please enter your service tag # on the link below, select the OS and then download the BIOS from BIOS section and then wireless card driver from Network section onto the Desktop screen. [URL] Please follow the steps mentioned below to uninstall the wireless card. After the uninstall finishes restart the system and install the drivers by using the file downloaded on the desktop screen.
Why is my WiFi dropping?
"DS:Why is my WiFi dropping?"