Macbook wifi networks disconnect and disappear after sleep in Yosemite

I have a Macbook Pro (Mid 2010 model) and ever since I upgraded to Yosemite I noticed my wifi networks disconnecting and disappearing after the computer wakes from sleep. I try to turn wifi on/off and no networks appear. The only solution I've found is to restart the computer which has gotten to be very annoying since I end up having to close all my work. Sometimes the computer completely locks up after sleep and restarts itself. I thought maybe it has to do with the SSD but that upgrade was made on Mavericks and I never had any problems until getting Yosemite.

Specs:

OSX Yosemite 10.10.2

4GB RAM

2.4 Ghz Intel Core 2 Duo

256 GB Samsung SSD HD

I looked over the fix below and it did not help.

How to fix MacBook, not reconnecting to wireless network on wakeup?