I think Virgin are wrong - The LINK I am sending you is part of a review of the product from Amazon which clearly states the setting up of XP & Win.98
This review is from: NETGEAR RP614 Web Safe Router with 4-Port 10/100 Mbps Switch (Electronics)
I picked this router up after doing some research on customer reviews on different brands/models. I was deciding between this RP614NA and the FR114P (also Netgear). I finally decided on this one after it ended up in my Amazon gold box with an additional discount. The router setup took about 20 minutes for 2 PC's sharing AT&T Broadband Cable. (One XP and one Win 98SE). Another 10 min and I had the network up and going (file/printer sharing). Probably would have went even quicker if I had more networking experience. As far as speed, I haven't noticed any drop by adding the router.
I can't advise further as I have never used this product but I have many friends with Netgear Routers who find them very reliable.