My Network Cards Stop Working

> this has been happening for about a month now! I have DSL with
> sympatico and connection thru a LinkSys Hub! every couple of hours my
> 2 network cards stop working, it doesn't tell me that I got
> disconnected thou! but when I try to go to lets say Google! it just
> tells me "finding Google.com" and nothing happens! as soon as I
> restart my computer it starts working again! it won't even let me ping
> another computer in my LAN!
>
> another thing is the DSL and Ethernet lights on my modem start going
> crazy (Flashing 2 times a second!) and as soon as turn of my computer
> they got back to normal.
>
>
> I use windows XP pro SP1, ~600MB Ram and i tried connecting my modem
> to 2 different LAN cards doesn't help!
> and i have a hub which connects my computer and wireless router to the
> internet! so its like this
>
> Wireless router
> DSL MODEM ====>HUB <
> My Desktop
>
>
>
> DSL MODEM: SpeedStream 5200
> i would really appreciate any hints!