windows authentication issue

[bhavesh]

i keep getting this message on xp professional..
".. windows needs your credentials.. " .. on clicking on
the pop-up .. it displays.. ".. lock your workstaion..
and unlock it .." .. the problem is that .. i have to
lock and unlock it.. in order to be able to authenticate
to network dives, databases etc.. can anyone help with a
solution.. thanks for your time..

-Bhavesh.