DVD not recognized

Hi,

I have a DVD/CDR-W Combo drive on my laptop, recently the drive doesn't
recognize any DVD's, Data or film. The drive is a Samsung SN-324F and my OS
is WinXP home. I have NERO and PowerDVD software that was bundled with the
PC when I bought it. When I put a DVD in the drive the light comes on and
tries to read it but nothing happens and there is nothing when I explore the
drive, all CD roms work and I can write to CD's. I have sent an E-Mail to
Samsung Tech Support and have had no response. Can anybody please help as
I'm completly lost.

Thanks

Gareth