iPod keeps rebooting itself, help!

Okay, it all started today when I installed "accentify" from Cydia, (Jailbroken) I restarted it and it started to come on but it stayed on the apple logo for about 5 min, and then it blinked and stayed there for about 2 min more. After that, it went to a plain black screen for about 5 min and started the cycle over, I read that if you let the battery die completely and then charge it, it should come on, I tried it and nothing happened please help.