I have just installed Mandrake 9.1 and everthing appears to have gone fine with the exception that I did not put in a username or password when prompted.

My reasoning for this is that I am the only one who uses the system and I presumed that if I did not enter one then I could boot the system without as with Windows.

Now however when I boot to the system it stops at the box for username and password and will not proceed.

Any help with correcting this would be very much appreciated

It is likely you at least supplied a root password. Mandrake did/does? allow a "no root password" so if you chose that simply type:
root
And hit enter, you shouldn't be prompted for a root password in such a situation. If you did, simply feed the password, and press enter. Now you can add users with things like:
useradd
And in the gui you have tools in the Mandrake Control Center as well as generic tools from KDE and Gnome.

Be sure to create 1 user and use that 1 user to do everything with, not root, root is only to be used for system maintenence, not for daily use, and shouldn't surf the internet (very much anyway).

Cool