Blank white screen for admin only

HI im still having issues with my site. Everything works well except the profile for admin when i click on it it gives me a blank white screen. www.mysite/admin. I have checked with my host there is no error other then internal error500 it says the only thing i think i change was playing around with the settings in fields builders trying to take away the the sex and looking for to make it an all female site and tried to block alot of the setting for members only not for visitors to view. I cant not think what i have made inactive?

Does it jump out at anyone what i have changed made inactive so i can make admin profile appear again as im able to do everything on the site still just not view my profile.

Failing that how can i get it back to how it was to start again working from the default.

Thank you for your help

Did you turn php display errors on like I suggested in the other thread?  Also please don't start multiple threads about the same problem.

http://www.boonex.com/forums/topic/Clicking-on-profile-the-screen-is-blank-.htm

Yes i did. it didnt show errors

Oh ok sorry about that.

Would you be losing much work if you reinstalled the whole thing? Sometimes that's easier in the beginning than trying to track down a problem. The other option is to go back and undo all the changes you made to the profile settings one by one until you hit it. 

No thank you .It was a 3rd party script  as suspected. Thank you again