Have you changed the nameservers to he new ones properly? Check if you have left any old name severs back there...
Btw this is normal pls wait for 24-48 hrs for complete dns propagation.
And every time you check your site, don't forget to delete ur cache and cookies, may be run ccleaner. Goto cmd ipconfig/flushdns...
This is all you can do. Your ISP also needs to flush their dns from their end. So just wait for a day or 2.