Installing and upgrading help

I have a disaster (for me at least). I just upgraded from 1.4 to 1.5.2 (following the upgrade instructions on the moodle.org site). When I accessed myhost/moodle.com/admin I got all 'success' message and then when I clicked on the final 'continue' I went to what looks vaguely like the moodle login page but with no graphics and a bunch of html/php in its place. Then when I try to logon as admin I cannot. When I hit enter after putting my admin user name and password, the screen refreshes and goes back to the same window with garbled text and the login window..........Argh!!! Why in the world did I decide to do this the night before classes start!!