Don't bump your topics in mere hours; Here in the N-Card forum it's common that topics go a day and a half without an answer.
Anyways, if we're gonna help you with your problems you need to be more specific. What games are acting up, and do you mean that they freeze and you have to restart your DS? The more descriptive you are, the better idea we have of the problem.
Right now, the best advice I can give you is to back up everything on your cards and update both of them to the latest N-Card firmware(Yes, it works on clones like the Fire Card) and xmenu.dat files. We have tutorials for such things lying around this sub-forum already, but if you need help, that's why I'm here, or probably someone, anyways.
Also, the newer firmwares set the save type of all games to automatic. Try changing them back to their proper format by holding select and pressing left/right. If you're not sure what the save type is, our release database has most of the info you need.