PLEASE I NEED HELP ASAP!!!!

i have a HP PAVILLION 550n and recently formatted all the drives and partitions and made a new partition. on that partition i installed a fresh copy of windows XP. upon completion of installation i realized that the display was at 16 bit colors and 800x600....i have tried changing these settings to get a better overall resolution..but it wont let me. i cant change the resolution or the bit display... did i do something terribly wrong? or is this an easy fix! please anyone that can help please throw in ur ideas and opinions..i was fixing my gf's dad's computer so yeah i need to fix this asap or i keep on looking like a dipstick!! thanks in advance!!!

ive allready ttried the right click settings and adjusting from there.. the tabs that let you adjust those settings are dimmed and not able to click..i havent tried going to the manufacturer's site for the monitor but i figured it was a HP monitor that should simply plug and play...thanks for the advice dietz....anyone else please?

i believe its unchecked by default...but i will have to double check that as well... thanks again by the way, it's always good to get a helping hand!!! )

yea Its Probably your Graphic Drivers.