Help! entire forum just returns blank white page
 

I'm moving servers,
I setup a test domain different than my current domain, in this:
-I moved all the files over to the new server
-I created a database on the new server and restored a backup
-I changed the config file to point to the new server
-Everything seemed to be working well


Then today I closed down the old vbulletin and made a new backup and restored and now the forum just returns blank white pages, no errors or nothing.

I tried another backup and restore and still nothing :(
I can access admincp directly, though there seems to be something wrong as the whole admincp style is purple and yellow (it's normally the default)

any help would be greatly appreciated :(