Unable to upload media to media library

Hi

All of a sudden WordPress stopped uploading images to my media library a week ago. It would complain of an unspecific error and ask me to try again later.
Interestingly this only applies to the media library, I can upload images to Next gen gallery without a problem.
I’ve disabled browser extensions, internet security,plug-ins, tried different browsers (I generally use Chrome), all to no avail.
The problem started in WP 3.7 and persisted in 3.8 (I thought upgrading might fix things. )
My service provider can upload to my WordPress media library without a problem so it’s something peculiar and local I’ve no idea what.

Anyone experienced anything similar? Or have any ideas as to what might be happening?

cheers

John