Sony Vaio media centre PC problemo

Apololgies if this has been covered I could not find anything on it.

I have a media centre PC - this came designed to output to an HDMI link TV with no vga option.
My Hard disk began failing / corrupting due to possible virus
I opted to re-install the software and have the re-install disks
However I also decided to format the hard drive in an earlier attempt to blat the virus (if this was a cuase of a range of pc problems) and try the rebuild option from the oem partition.
Everything has worked fine before for 3 years and the HDMI link was working up until my attempt to rid myself of the virus/problems the PC was having

What I have not been able to do is get any output to the TV since formatting hard drive.
I have tried with the rebuild disks, they are I believe doing soemthing but as I can't see what is happeining I have no idea what is being asked of me such as press enter to carry on etc....

I have also moved the disk to another desktop I have and tried loading the rebuild disk but as it is not a sony it bails out.
I then loaded a copy of Xp onto the disk using the other PC and it works fine
When I put the disk back into the Vaio i still get no output.

No Bios option is availaible to me on screen either

Sony is their wisdom have no VGA diagnostic port as far as I can see and the S video is input only

Any ideas? The Model is Sony Vaio - PCV H21M