Screen resolution setting not persist on xp

[mach_621]

Hello,
- I have installed Windows-XP on PC.
- After that i have set the screen resolution to '1440 by 900 pixel'. It works fine
- But when i lock (windows-key+L) screen and unlock it after 10 minute, it again set to '1040 by 768 pixel' automatically.
-> I really do not understand why this happing..
Please help me...
Thanks in advance

 

[penguintech]

who is the manufacturer of the Screen that you are using?