Cannot connect pc to 42" pdp

[bytes2]

Trying to connect my pc spec athlon 2400+, 512 ram, 9700 pro to samsung
42" ps42e7hd.

Works ok when connecting with s-video but get blank when using monitor input using d15 monitor cable. Infact cannot select Pc mode on tv because it is greyed out.

Any ideas guys.

 

[GrahamN]

The only thing I can think of is that you may have a resolution not compatible with your pdp. Most pdp's run at 1024x768 and some will not show a desktop above this resolution.