can no longer use my pc through my hdtv pls someone help this is very strange issue!

[jay2006uk]

hi guys please could someone offer some advice on a very strange issue im having when trying to use my pc through my hdtv. ok the situation is this.... it use to run fine my graphics card had to be set to 1360x768, one day it stopped working so i thought it must be the tvs pc input gone wrong, so then i thought i would get around the problem by buying this converter that converts vga to hdmi as my hdmi sockets working fine, i set this box up and still nothing and like i say hdmi socket is fine so now im starting to wonder do graphics cards have any setting u need to change for them to work on hdtvs? also to note is when trying either the oc socked or hdmi its partially doing something because u get that sound from the pcs sound when somethings been plugged in and when u unplug it. if someone could help me i would be so gratefull because its something very strange. thanks for your time. james