LCD is not priniting what it is told

I have a serial lcd from sparkfun that is connected to the boarduino via the Tx pin. I had the LCD working, printing out what it needs to print out, but after i put a new program on the boarduino the LCD has refused to display the correct things. Now it only displays a 0 in the first place, and the rest are solid blocks. What ever i tell it to print out, it prints the 0 and solid blocks. Can someone please help. This is really frustrating. Thanks.

Also is there a way to restore the LCD to factory settings

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1207941087/0