Well kbennet, here was I thinking I was intelligent enough to work out the blatantly obvious. I read your 'check your computers time and date' advice and thought 'pfft... what does he think I am? Some kind of idiot?' but I checked it anyway. My PC thought it was November. Insert sound of hand slapping forehead and a Homer-like 'Doh!'. Changed the date and, surprise, everything is back to normal. Thanks for your help kbennet and thanks for stating the completely obvious. I will now go and sit on the not-as-smart-as-you-thought-you-were-are-you? bench with all the other eejits.