Code inserted in to my templates.
 

Hi I wonder if I could ask for some urgent help.
I'm running vb 3.8.
Someone has managed to add some code to my vB implementation that is calling a nasty script.
However I can't see any changed php files or templates.
Anyone ideas where I start with finding out what's happened here?

HTML Code:


The attached source shows where the nasty iframe is getting embedded.
Any help much appreciated.
Thanks
Dave