Cannot connect to MAC Airport network. Message: Wireless network connection does not have IP configuration

We have Mac's and PCs at my house. The wireless connection is through Airport and has been working perfectly well for many years, probably 10 or more. The WEP key is 20 letters and numbers long and when my children come with their Droids and iPhones, they always complain about the length so I decided to change it yesterday. Bad choice!! I was able to connect the MAC laptop wirelessly but not the PC since it told me I needed a 5 or 13 letter key. Meantime, the main computer connected to Airport, a Mac desktop, was not connecting to the Internet. However, the laptop was and is. I spent hours on this yesterday. Today, I reset the cable modem, the Airport and rebooted. The main computer connected but just for a while. I changed the WEP key back to the original long one. Nothing I do to the Mac desktop brings back the connection but it doesn't matter since it is an older computer and the MAC laptop is connected with no problems. The PC does see the network but cannot connect because it says the there is no valid wireless IP configuration. I have read other messages related to the IP problem and have followed directions downloading drivers to no avail. I am now connected using the tether from my Samsung Droid. I am attaching the IPCONFIG text file another user was asked to attach to see if it sheds any light. I need help! I am at my wits end since I am a free/lancer and get my jobs through the computer. For several reasons, it's better through the PC that the MAC. Thank you!