Xbox 360 - Low res graphics bug

hey i recently got my xbox setup so i could play some of the games i loved but the resolution looks so low, i read that you can go to system settings - > display and change it but i don't have a HD tv, the change only seemed to come about after i changed my computer's resolution but i don't see how that can have affected it

how can i fix the low res?

@jkanjm2:

What connection are you using and what are you plugging the Xbox 360 into?

If you have a standard definition television you wont be able to use the HD resolutions (i.e. 720i, 720p, 1080i, 1080p) as they require a HD ready display. However, from what you have said, you are using a VGA monitor to display the Xbox 360 console output?

@Garfield360UK: no sorry i wasn't more detailed, i use a panasonic television as my computer monitor, i have both my xbox and pc hooked up to it (pc through vga and xbox is into av1) and when i first got my pc i'd switch between them and they were both fine, but a couple of days ago i re-hooked up my xbox so i could play some gta V and the resolution looks so low, the graphics look fuzzy I guess is the word :/ i am not sure why