Hi Ann,
Sorry to hear you and your machine are not friends!
When I had problems with the needles not being selected properly, I found working the selection mechanism by engaging the switch on the carriage and moving the carriage back and forth gradually loosened up everthing. I had to put fresh grease on the selection drums (the things the timing belt fits round) and that helped too.
I have just bought myself a Brother 864 and as I was answering your question, thought I'd check the punchcard selection on it as I haven't been able to use it yet. Having switched the knob to KC I tried pulling forward a few needles and guess what - they didn't stay selected but kept changing position with each pass of the carriage. I then tried card 1 and the same thing happened. I removed the carriage, moved the change knob several times and checked it was moving the cams under the carriage. Having replaced the carriage and switched it back to KC, worked it over the needles several times, it is now selecting needles for card 1 properly. The mechanism does get stiff when not used for a while and by working it without any yarn threaded, it may be possible to get yours working. Card 1 is a good one to try as you can see easily if the right needles are being selected. If after trying this, you are still having problems, it would suggest that your machine needs to be looked at by a qualified engineer.
I do hope you can get it sorted and you become friends again!
Sue