I can't tell from what you wrote if you have addressed your display settings. http://support.microsoft.com/kb/976064
shows how to do it along with screen shots . You can get to display settings several ways. I tend to just right click on empty area of desktop and select properties and then settings. Your monitoring devices do need to be on in order for the computer to find them. You can set up the resolution for each and designate which is primary. If you tend to switch back and forth between single and dual monitors then you may need to reset this more often.
I am also unclear if you have addressed changing the input on your tv, if not then simply set the source for input.
It might be helpful to others attempting to help you if you say what you are using for each monitor and then referencing it that way. At least for my brain using the words "this" and "the other" tends to get confusing in very long sentences. Others may also find that they need to know your operating system to give you specific instructions.
Good luck and sure you will enjoy this once it is up and working.
Hi there i got my computer some time about 6 months ago and have decided to set another monitor up but im having trouble with it this is my computer http://www.overclockers.co.uk/showproduct.php?prodid=FS-244-OE I have a gtx 680 and iv hooked a two monitors up via 1x dvi i and 1x dvi d the dvi-d tho (i believe its this) is dvi-d with a hdmi on the other end going into my tv/monitor i get the display through the other monitor (dvi via vga) but i dont seem to get it through this monitor it says no signal input but if i connect this to my tv (dvi-d with a hdmi) and run the dvi via vga to my monitor/tv then that works just fine could anyone help me out here and point me in the right direction im clearly going wrong somewhere but i dont know what im doing wrong im a complete noob at duel monitoring and this is my first time help is appreciated and thanks again guys.
Also attached two shots at the bottom for you guys if that helps?