Apart from the stray </font> tag?
No <body>, no enclosing block-level element (<p>, <div>, whathaveyou), which is where the alignment is supposed to be specified.
Apart from that - what's the problem?
I'd recommend some introductory tutorials on HTML and CSS, but I don't know the current crop. But I do find that attempting to have some idea of what you're doing is more productive than firing stuff off at random and then asking why it doesn't work. At least fire stuff off at random and then try and figure out for yourself why it doesn't work.