[Solved] Admin login screen

[rudders18]

Hi,
I am relatively new to Prestashop having used Zencart before but so far I am very impressed. I have an installation that has been working fine for a week or so but now I suddenly cannot login to the Admin screen. When I type in the credentials the screen just refreshes and comes back to a set of blank ID and password boxes.

It lets me know if the password is blank or if I try a non existant admin user and I can reset the password, receiving the mail as expected.

I can look at the server logs and the only error I see is a reference within login.css to a non existant image file, nothing else.

Has anyone got any ideas as I do not want to have to re-install the files again, the actual shop seems to work fine for normal users.

Thanks in advance
Paul

UPDATE
An update to this is that I have managed to get to the back office screens by not using the url www.photo-gifts-direct.co.uk/admin123 but instead using 85.13.219.66/~photog/admin123. Any suggestions as I do not know PS well enough and do not have the time to track down this problem.

UPDATE 2
As this is almost a live shop I persevered till I got a result. I tried most things aid in other posts about cache and cookies but nothing worked and I am not 100% sure of the fix but it is related to the .htaccess file and the PS Directory entry in the Back Office Preferences tab. I copied across the original htaccess.txt file and renamed it, accessed the Back Office by using the IP address version of the url and then blanked out the PS Directory entry as it was showing it is installed in the ~photog directory when in fact it is installed in the root of the domain.

This has fixed all of the problems, friendly urls work, access to the admin screen now works. I think this problem arose because the install got confused even though no errors were given because I installed the shop using the IP based url and not the normal domain name as the domain name was not directing you to my new host due to the DNS propagation time.

Hope this helps someone as there are lot of posts relating to this or similar issues.