I have a serious situation here. My first black N64, had a jumper pak, so I needed an expansion pak. I buy one made by Yobo, and when I try it, it doesn't work, when I switched to the Jumper pak it worked, then i switched back to Expansion pak, and the system won't run anything now even if I switch between paks. I ordered a ice blue n64, and it came with an Expansion pak made by nintendo. Since I couldn't return the yobo one because I lost the receipt, I tested it with the new n64 I got because I wanted to see if I could trade it in, and guess what...now my new 64 won't run anything with either jumper pak, nintendo expansion pak, or the yobo expansion pak. Please help...I have 2 Nintendo 64's that wont do anything now >.>.