Help Needed - Site just shows blank page

Hi, im quite familiar with how zencart works, the site in question is on 1.3.8a and basically all i did was upload a new image then set that image as my new header, then on checking the site it just gave a blank page, so i thought i must have left a comma out or something but all seemed correct, so i added my old header back but that too just gave me a blank page. I then reinstalled the back up i made and that still didnt work, so i turned to my hoster who tried their mirror back up from 2 weeks previous still without success so i now turn to you guys for help. What could i try that i havent yet done.

Thanks
Ben

I have managed to sort it out, I completely deleted the database and reinstalled it, during which i figured out what caused the problem in the first place.

In the main files, i think the encoding option is set incorrectly as when i edited a page in another website a similar thing happened, but luckily i was able to cure the fault straight away by using a copy/paste of the origianl page. What should the encoding be set to as mine is set to us-ascii whichi think is is causing this </a>'); to be added to the end of each paragraph.

can anybody help