Ok, so my V5s just LOVE resetting themselves for no apparent reason, and both of them too. I's really annoying, and I lose my gens, too! how can i stop this???
Try taking off the battery cover and cleaning around the reset button with a Q-tip. If that doesn't work, change the battery. If you are still having difficulties, e-mail Bandai's customer support. I had an old Giga Pet that did this; I put some tape on the battery cover to keep it more tightly closed.
OMG that used to happen to me its so annoying I know why it happens. It happens because the reset button is to far out. Apperently the v5 reset button is very sensitive so when you put your finger anywhere near the reset button it resets itself I fixed it by opening up my tama and taking out the reset button LOL! Try it.