|"Is Firefox 3 old? No, it isn't. From Oldapps.com: Firefox 3.6.28 07 March, 2012 (2 months ago)|
That means Firefox 3 isn't old"
It means it was posted to their site in March 2012, that is NOT when it was released. Firefox is currently at version 12.
"Firefox 3.0 was released on June 17, 2008, with Version 3.5 and Version 3.6 released on June 30, 2009 and January 21, 2010 respectively. Version 4.0 was released on March 22, 2011. With Version 5.0 onwards the rapid release cycle was realised which envisions a new major version release every six weeks on Tuesday. The latest version, Firefox 12 was released on April 24, 2012."
"Firefox 22.214.171.124 is the final version which can run under an unmodified installation of Windows NT 4.0, Windows 98, and Windows ME"
See: History of Firefox
You haven't listed your complete specs so it's difficult to give a complete answer. But you said you want to connect via an ethernet cable so why are you concerned about the wireless card? Remove it from the system. It's not supported & may cause conflicts. Does your motherboard have onboard network/ethernet?
WinME isn't going to help you. There are no Win9x/ME drivers listed for the X800 at the AMD/ATI site. Do you have an older graphics card you can drop in? Assuming you have an nForce2 based board, I see there's a legacy driver package available from nvidia:
I think you understand the need to reduce the RAM amount to 512MB or less to be able to install Win98? And then the tweak that needs to be made to the System.ini file before bumping the RAM amount up again?