Are you installing Win 7 32bit or 64bit?? 

You machine doesn't have drivers for win7 period. You are a 32bit Machine made for WinXP 32bit and Vista 32bit, thats why your having troubles.

If you are still running Win7 and cant find a working driver, make sure its 32bit then find a external Ethernet card like this one from Dell site:

<ADMIN NOTE: Broken link has been removed from this post by Dell>

Try this site: http://www.driversguru.com/driverdetail/1922669-Intel+(R)+PRO+Wireless+2200BG+Network+Connection,+(R)+PRO+Wireless+2915ABG+Network+Connection,+(R)+PRO+Wireless+Network+Connection,+v.11.1.0.0+(TIC135897)+,+A02

R154405.EXE 

PCI\VEN_8086&DEV_4220&SUBSYS_27228086&REV_05 =  Intel PRO Wireless 2200BG

Download The intel calexico2 driver for Win7:

http://ez93.com/dl/pci-ven-8086-dev-4220-subsys-27228086-rev-05-4.html