Insprion 6400 resolution help?

Hello,

I gotten this laptop around 2005-2006, it's a great laptop and I use it all the time. It originally ran on Windows XP Home Edition, and the resolution was 1280x800 or somewhere between that (I couldn't remember). Around 3 years ago, I upgraded it to Vista and I like that OS too but I today I wanted to downgrade to Windows XP Home Edition. I downloaded all of the correct software and drivers for it from the Dell website since the disc didn't have the original hardware in 2005-2006. Now, when I was using vista, I remember it using the resolution 1280x800 before I formatted my hard drive to install Windows XP. Now, here is when the problem comes in: The only 2 resolutions I can switch to is 800x600 and 1024x768. I really want the 1280x800 resolution but I don't know how to. I think my laptop used to run on Intel by the stickers on the laptop but I removed it a long time ago. Can anyone help me out on this?

Thanks.