Impossible. You need the salt as for security reasons passwords aren't stored in the database - only MD5-Hashes with a salt to randomize the results.
This makes it more difficult to crack passwords, as MD5 itself is not collision-free.
But you could simplify the login very much, avoiding almost all "vB-Overhead".
What exactly do you want to achieve?
What I want to do is this.. in http://vac.dndweb.net/forum when someone tries to log in on top and click 'log in' the action page only looks for the username and password. If the query recordcount is 1 (meaning it was found) then you are successfuly logged in if not you get an error.