that happened with my LG TM510. i tried all types of shit to fix that problem.. the thing that worked most often was blowing on the contacts on the battery. it prolly didnt really do anything, kinda like i used to blow into my nintendo games.. but it seemed to work. the other thing i'd do is just keep pulling it off the charger and back on again until it stayed solid red. i just said fuck it and bought a new phone.. and since you have sprint, you can just go to your local best buy and purchase new one without any extra charges, unlike cingular and verizon who make you wait a certain number of months before you can buy a new phone.. check out the sanyo8100 or the samsung VGA 1000.