Now this one nagging feature of Win xp that when one user sets the display screen resolution it is set for all users ! For example your father may like higher resolution for reading stuff but your younger bro plays games and wants 800 x 600 , and it becomes irritating for not being able to a custom display.
Here is a simple solution :-
1) First download this - MultiRes
Don’t worry its safe (tested on my computer)

This is quick resolution changer, that can change the resolution setting in one click. For most of us this should do !
But we are taking this a step further to automate the changing process as soon as the user logs in by batch files (yeah it is safe too !)
2) Download This - Changeres batch files
In this zip file you get 3 resolution settings at color depth 32 (you can edit them in notepad for the setting you want eg refresh rate / color depth etc)

Here comes the auto settings part !
3) Copy/extract the settings file wanted to the startup folder of the user
Go to C:\Documents and Settings\USERNAME\Start Menu\Programs\Startup

Replace the username with the windows user name you want and paste the correct settings file.
4) Done ! Next time you login to that username the batch file will be lauched and will change the setting automatically.
To remove this just delete the file from the above mentioned folder !
Enjoy..!!!

thanks for the info

for your efforts and sharing.