I am on a Mac OSX 10.5.4 with an Airport Extreme Base Station. I have a Dell PC that used to function with the network just fine until the DSL line failed this week. When I tried to get the Dell to connect to my Network, it will not. I tried to reset the WEP Key to match the Apple but it is not working. How can I get the PC to connect to the Airport? Thanks in advance!

Already Tried:
1. I have tried the obvious of turning all the networking equipment off, and then back on. Initially the PC will see my network "Deborah's network", then it falls off and won't reconnect.

2. I went into the network settings on the PC and chose my network from "Available Networks"
Then I chose "Access point [infrastructure] networks only
For encryption I chose "WEP'
Authentication mode "Shared Key" and said "ok"

My PC continues to drop "Deborah's Network" and reconnect to an unencrypted network far away from me. Then I drop off the internet. This happens consistently. Something is wrong.
FYI--my PC has been cleaned of viruses, has a new Virus Protection software [MacAfee], new memory [2 gigs] and a new battery. Should be working well. It's a Dell XPS M140.

The Mac is working great with the network. No problems there.
Thanks in advance.