[Opserty]

You can't reset the password via. phpMyAdmin alone, you'd need to generate the password hash first. Otherwise any password check would fail...

Is it possible for you register another account on your forum? If so:

1. Create a new account, username and password don't really matter as long as you remember them. (We'll call this User B, User A being your old account).
2. Upload tools.php, to your admincp directory, from the do_not_upload folder of the vBulletin archive.
3. Navigate directly to the file (type in yourdomain.../admincp/tools.php)
4. Follow the on screen instructions and use the option to "Reset Admin Access" (do this for the User B account).
5. Log in using the User B account and reset the password for your old admin account, User A, (through the AdminCP).
6. Then when you're done you can delete the User B account you'd just made.
7. Don't forget to delete tools.php when you're finished