|I believe you have made a typo.|
It's supposed to be d:\i386\dosnet.inf
(Not \i306 . I used i instead of capital i - I - because it's hard to tell what it is in some type fonts.)
The \i386 folder has almost all the files and folders you need to install Windows - dosnet.inf is one of those files.
Is the D the second partition on your brand name system hard drive, or is D your optical (CD or DVD) drive letter?
Brand name computer original software installations often have the \i386 folder on the hard drive somewhere so that you don't need to insert a Windows CD when you install certain Windows features.
If D is the second partition on your brand name system hard drive, dosnet.inf is probably corrupted. You need to replace it with dosnet.inf from a Windows CD of the same version as your Windows installation - e.g. Home or Pro.
If you are the original owner of the laptop, most Dell models that came with XP on them came with an XP Re-installation CD. That can be used the same way as a Windows CD with your computer.
Dosnet.inf is in the same place - in the \i386 folder on the CD.
If D is your optical (CD or DVD) drive letter, and if you're trying to install Windows from a Windows CD, or a Dell supplied XP Re-installation CD, try cleaning the laser lens on the drive.
Use a laser lens cleaning CD in the drive - if you don't have one, places that sell CDs and DVDs often have them, and even some "dollar" stores have them for a buck or two.
Or - eject the optical drive's tray, and with no disk on the tray, wipe off the obvious laser lens with a tissue or a soft cloth.