Hi stefyboy - Below is a link where you can download your driver. After you get to the page just make sure it says Windows XP as the operating system. Then scroll down and click on the + next to where it says network. You want the intel 10/100 driver. I've included a few a ways to install it. If your kinda new to this the easiest is the download to desktop method and just remember where it unzipped it to, you can always move it to a driver directory where you can keep all your drivers for the future.
http://support.dell.com/support/downloads/driverslist.aspx?c=us&l=en&s=gen&ServiceTag=&SystemID=DIM_P4_4600&os=WW1&osl=en&catid=&impid=
If this solves your problem PLEASE rate this as fixed. If not, DO NOT RATE YET. Just add a comment letting me know what happened and I'll be glad to assist you further. Thanks.
Jeff
Hard Drive Installation (via WinZip) with HTML Pop-Up Window for R67150.EXE
Download
1.Click Download Now, to download the file.
2.When the File Download window appears, click Save this program to
disk (Windows XP users, click Save) and click OK. The Save In: window
appears.
3.From the Save In: field, click the down arrow then click to
select Desktop and click Save. The file will download to your desktop.
4.If the Download Complete window appears, click Close. The file
name icon appears on your desktop.
Install
1.Double-click the new icon on the desktop labeled R67150.EXE.
The Self-Extractor window appears.
2.Click OK or Continue.
The Self-Extracting Driver Installation window appears and prompts to
extract files to C:\DELL\DRIVERS\R67150.
3.Leave all of the default settings and click Unzip or OK. If the directory doesn't exist, you'll be prompted to create one. Click Yes. A Self Extractor window appears and indicates C:\DELL\DRIVERS\R67150 files were
extracted.
4.Click OK.
Follow the on-screen installation instructions in the window.
HTML Pop-Up With Install Now Button
1.The Dell Software Installation Documentation window appears.
2.Click the Install Now button. A File Download window appears.
3.Click Run this program from its current location and click OK.
The Security Warning window appears.
4.Click Yes. The InstallShield Wizard window appears.
5.Follow the on-screen instructions.