DVD drive no longer reads dvd

Hello,

I have one internal Sony cd drive , one internal combo drive (model Samsung CDRW/DVD SM-348B) and one externally USB connected dvd writer (model-Samsung TSST Corp CD /DVD SH-S182D) .DVD writer is basically a internal drive but connected externally using a Advik USB 2 casing.I am using Windows xp

Sony cd drive,which is only a cd reader, is working fine.

The combo drive does not read any cd or dvd.When a disk is inserted in the drive , computer remains busy for some time and finally shows blank in the drive. It does not recognize any cd/dvd in the drive.

DVD writer is also not reading any cd or dvd.When a cd or dvd disk is inserted ,following message is received

G:\is not accessible
Incorrect Function
'G' is the drive letter of dvd writer

It is giving above message even with a data dvd burnt last week using Nero on this very dvd writer.

I did search internet without any success. I shall be grateful , if you could help and guide.

Yours truely
akm.


Yours truely
akm