New IP, now I can´t login, please help

Hi

I have my wife´s wordpress on the Synology NAS. I have worked fine (slow, but fine), now we got a new IP. When she try to login it use the old IP and it fails.

Well I have checked the wp_options URL and SITEURL is right. The fail comes when she does this:

1. she types the URL – abc.com and enter (after new IP, its very very slow about 2 min.)
2. the site appear (but no pictures?) she click the login button
3. old IP appears oldIP/wordpress/wp-login.php
4 she change the url to newIP/wordpress/wp-login.php and the login site appears
5. she enter the name and password, tab the login button, and the url change back to oldIP/wordpress/wp-login.php and nothing appends.

How can I fix this? I hope somebody can help me very fast