I've recently had a few clients that experienced their WiFi signal dropping from their laptop after they've updated it from Windows 8 to 8.1. Usually this is caused by a bad or outdated networking driver. Here is a quick way to solve the problem, but you will have to be connected to the Internet so make sure you are currently connected by WiFi or preferably with a network cable going directly into your modem or router.

Right click on the new (for Windows 8.1) Start button at the bottom left of your screen and then click on Device Manager

This will open up the Device Manager window. Next you will click on the "Network Adapters" which will show all the Network adapters on your computer.

There will most likely be two or selections when you click on this. The one you will be looking for will have some mention of "wireless". Next right click on the adapter and choose "Update Drivers". The computer will then search online for any updates for your network adapter and install it. You will then have to reconnect to your WiFi.

Your WiFi connection should now stabilize.