UPDATE:
I've been working on the server this morning and have updated many of the files that could have been infected with the virus thingy....
So far, I haven't had any experiences of the blank page or anything so hopefully we've caught it.
I've also downloaded the new Version 2.0 all-singing-all-dancing version of the software. Flushed with my success I'm wondering if I should try loading that too...?
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Anyhoo... Keep an eye on the forum and let me know if you have any issues. I won't add the extra bits back in 'til we are sure it is all working.
That is all...