[TYPO3-english] TYPO3 4.4: can't access backend

[Luis E. Suarez]

Hello,
I wish to upgrade all my sites from old TYPO3 versions.  For testing 
purposes I have installed TYPO3 4.4 in a Windows 7 machine and 
everything went smooth.  Imported all content from an existing site (ver 
4.1.15) and worked just fine with all the required extensions included. 
  Then installed ver 4.4 in the same site on a new folder using a new 
empty database.  Installation was okay and passed all configurations, 
however, have no access to the backend using the default admin and pass. 
  Created a new admin and still can't access the backend.  The backend 
page renders blank for a second and reverts to the login.  The server 
log says nothing.

I have installed TYPO3 many times since ver 3 and never had such strange 
result but at this time I run out of ideas.

Will appreciate any help.  Thanks.