No you dont need it, but even though you uninstalled it, its still there in the background, but what I have to do everytime I reboot, is to enable/disable QoS to even get the connection working, check my previous thread about this here: http://www.antionline.com/showthread...hreadid=241575
Finally, I tried to disable QoS, nothing... I enabled it again, nothing, I pulled my hair for a while, nothing... then I disabled QoS again, viola, I was online.

Now, my problem is, I have to enable/disable QoS in winXP everytime I reboot since then (*nix users, dont laugh). I've spent days searching for anything like this in MSDN, and nothing, seems like this has only happened to me, ever.
Now I don't have a clue if this could somehow relate to the problems you are haveing, but I thought it was worth a shot
You can get it back by installing it again in the properties for your dialup connection