LG B2000 turning on problems

[bnza8]

i got my mum an LG B2000 and for the first couple of weeks it worked very fine. but recently its been having problems, when im trying to turn it on it doesnt seem to want to. every time it doesnt work she has to take the battery out for a few minutes and then put it back into the phone. and most of the time it will work.

any suggestions what i should do other then go to the shops and get it fixed?

thanks.