Desktop to big for my tv and wont adjust... my video card is nvidia geforce 7300 LE?

i just bought a DVI to HDMI cable and hooked it up in place of my s-video and my desktop is to big for my tv and i cant adjust it at all, i dont have a moniter, my tv is my main screen and i have downloaded all the drivers and control panels i could find, anyone have any ideas? other than it being to big the picture looks better than anything else ive had|||change the resolution. For vista press start and type personalization. Choose display settings and change resolution from there. For xp right click an empty area of the desktop and choose properties, choose display tab and change resolution.|||should have to run the monitor wizard again. it should detect your screen and adjust automatically