my resolution had changed so i changed it back 1024*720 but its not what i exactly wanted!
"back to normal" and "what I wanted" are not very good terms to go by. It's like going to a random city, walking into a coffee shop and telling them "give me what I usually get back home".
Move the resolution slider around till you find one that works for you. For best quality, look at the monitor manual for the native resution and set it to that like Hawkeye22 said. If you post your monitor brand and model we'd be able to find that for you.