i played around with desktop settings because some game sites have really small boards and font size. now the height for everything above the web page itself is way too high, taking up 1/4 of the total height when i opne the browser. how do i undo this ?

i don't know if this is a web issue or a computer/monitor issue. excuse me if this is not something you can do for me. on every web page i have to zoom out. also, whatever the "bars" are called, where the X and minimize icons are, the open tabs line, the web address and google search lines, all are too large. i screwed up. also i can't change the dpi setting from 200 back to 120. is that what's doing this ? should i go to the windows xp tome ??