Problem booting up without power cord plugged in.

I have an lg ultimate 2 phone that would boot up and down with no problem until recently. the phone is about 2 years old.

I power the phone down at night and back up in the morning. now the phone won't boot up. The lg screen just hangs and the notification button at the bottom cycles through a few colors (I think that's an error notification).

The first few times it did this, i could just take the battery out, put it back in and it would boot up ok. Now that won't work unless it's plugged in to an outlet, but it does still work.

I called trakfone. They told me that I'd have to have my phone basically factory reset.

I asked if that was just a troubleshooting step, or could they say it would 100% fix the problem. It's a troubleshooting step.

I don't want to do a hard reset if it's not going to fix the problem. the battery is charging and discharging just fine - even when not plugged in. it's just not booting up properly.

Anyone think I should just back everything up and do the factory reset?

Thanks.

Patty Rowland