once you have it running save all your photos and music contacts and other data you want to keep to another device either a sd card or jump drive or computer. Once you have your info saved then do a factory reset. This will return your tablet to is original factory state and should restore the original performance . This guild you through the process
http://support.triotablets.com/hc/en-us/articles/201746559-What-do-I-do-if-I-forgot-my-password-to-unlock-to-my-tablet-
Hope this helps