Login/Join popup block problem

My  Login/Join popup block showing half a width of what it supposed to. Since I didn't do any modification to any part of the main core code and didn't install any new module, I was wondering if anyone else has this problem? Also any help to fix this will be really appreciated.

I have attached a snap shot of the popup block for your reference

Hi My Friend,

Without being able to see what your CSS settings and access to the sites php files , it's impossible to give you an answer but to get around this problem if you visit a post I made, this may help you out.

https://www.boonex.com/forums/topic/Open-join-php-and-not-popup-box-on-splash.htm

Good luck

Gew