Hi, I specialise in repairs to Sony Ericsson mobiles, this is a comon problem, depending on the precise fault, it could be simply a software issue with the phone.
At worst, the screen may be faulty, a new screen is roughley between £5 and £10 max.
I carry out repairs to these phones for a fixed fee of £5 which includes the return of the fixed phone to you plus cost of any parts but you only pay the £5 upfront.
For details txt me on 07864184064
International +44 78641 84064
Andy
July 2011