I have etherfast cable dsl router V.2 to which I

Here are a few links that may help you to sort this out...
Start here and here. (Make sure power management checkbox to save power is unchecked.) Here's the vista networking home page, and here and here are just a couple of the vast resources available at this great site.
Finally, there are specific resources geared toward troubleshooting the installation with your particular router accessible from here.
I recommend you take a look at the Linksys guides first, then work through the MS vista guidelines for setting up a network, & make sure you've followed their protocols for 2 OSs, and then begin to troubleshoot the installation from there...

I hope this information allows you to resolve this issue. If you need further assistance, please post back with a comment to this thread.
If I've managed to answer your question or solve a problem, please take just a moment to rate this post....thanks!