Your system has either PC Restore, if it came shipped with XP, or Vista System Recovery. Either one of those can restore the operating system and all of the drivers and applications that came with your system. Here's the link to instructions:
http://support.dell.com/support/topics/global.aspx/support/dsn/en/document?c=us&cs=19&dl=false&l=en&s=dhs&docid=3E48AE3870775D64E040A68F5B2877D4&doclang=en
Hi
I have a dell E 1505 that's a couple of years old.
The original system CD disk has been lost.
I'd like to reformat, repartition and reinstall WinXP or Vista & the model specific drivers.
Or even replace my current HD with a new, blank HD.
I have a generic CD for the XP OS.
How can I find out which model specific drivers I need and download them?
I have a service tag but the dell website still lists loads of things I don't need, so doesn't seem that aware of the details of my system.
I know there is a small partition on the hard disk that seems to be dell specific.
Do I need to keep this partition? Why is it there? What software is kept there and why does it need to be on its own partition?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic