Logon Username & Password Fails on At Work Network

>I am trying to connect Vista Ultimate based Laptop to my at work network (A
> Server -W2K along with broadband internet connection, that uses routers
> and
> ethernet cables).
>
> I use map network. I use a server name & I am asked for user name & p/wd.
> (I believe my server name is correct -because when I deliberately use a
> different server name, I do not reach the dialogue box asking for user
> name &
> p/wd).
>
> I enter my only administrative privileged username along with the password
> assosiated with the user name. Two things happen: System modifies my user
> name to incorporate my computer name (what I feel is normal). I get a
> message
> 'Incorrect Username &/or Password'.
>
> I pinged the server. It works with 0% loss.
> I tracert my servername & server address. It works.
> NSLOOKUP rezults are ok.
> DNS Client (in services) is set to Started & Automatic.
>
> Thank you for helping me connect my laptop with at work network. (I hv
> access to network adminstration level -however any changes on server W2K
> would be tricky for that the network is busy all the time)
>
> The other 4-5 desktops on network use XP.