Right, ok.. What you need to do is disconnect them all in my computer (right click each drive and choose disconnect) and then do the following..

open up a command prompt as before..

Type the following commands...

net use w: \\mattloaf\pictures /savecred
net use x: \\mattloaf\files /savecred
net use y: \\mattloaf\video /savecred
net use z: \\mattloaf\music /savecred

It will ask you for the username and then password.. so enter the user name and then the password when it prompts you.. you should only get prompted for it for the first one above, the other 3 will just re-use the same credentials..