Solved!!!!!!
The darn memory card was bad in the sense that the Legend HCx was not able to read it. But, it seemed fine on all three of the computers we have at the house. By chance, I put the 4GB Sandisk card from my Centro in it, and it WORKED! Yeah! I then talked to Garmin and they said that the 4GB shouldn't work, but it does. I loaded all of the City Navigator Maps for the whole United States and all of the Topo 2008 maps for the Western states (About 1,900 MB). I know this was overkill because I rarely travel outside of California, but I wanted to make sure that it really was working. Garmin did tell me that they will send me a 256MB card to replace my defective 128MB card.
I have since been using my Legend HCx all over town, and the Salton City area. I am impressed with the unit. It is a lot better than my old Legend. I really like how easy it is to send a huge list of geocaches to the unit, and not have to enter them individually. I don't think my old Legend was able to do that. Also, it doesn't seem to lose sat signal, not even in my house! I just hope that Garmin hasn't sent out too many of these with defective micro SD cards.
By the way, THANKS EVERYONE!
Jeep Del Fuego