When Reinstalling Windows you will always need the following most important drivers :
1. Chipset Drivers : http://support.dell.com/support/down...&fileid=149851
2. IDE/EIDE Controllers : http://support.dell.com/support/down...os=WW1&osl=EN#
( You need to get the most appropriate ones for your hard drives/Hardware. )
3. Display Drivers: http://support.dell.com/support/down...os=WW1&osl=EN#
( As with Above you will have to get the correct version for your hardware. )
These are the most important drivers for basic setup and Readines.
However for your Lan drivers so i can help more can you tell me the make of them at all as they could be the Realtek lan.
Check out Realtek Drivers here : http://www.realtek.com.tw/downloads/
Also check out my Windows Faqs in my sig .