My Palm Centro keeps freezing and turning off after hotsync messa

My Palm Centro has been working fine for a couple months, but today it did the EXACT same thing my last one did. It say ''HotSync'' and turns off and will not come back on. I took the battery out for a couple hours, put it back in and it worked!....for an hour. Now it says the same thing and wont come on. I never installed the CD that came with it because I use it for nothing but calls and texting. I took the last one back and got this one and just charged it and put my sim card in and it worked perfect until now??? what could be going on? any advice?