WD elements external hard drive was working yesterday!

Hi,
I have a 1tb WD elements external hard drive and I was merrily watching half a film on it last night and today I try to watch the other half however, now my computer doesn't seem to see it when plugged in. The hard drive was making this repetitive clicking noise yet now it doesn't seem to even be doing that. Bit scared that all my travel pictures that are on it might be lost forever. Does anyone have any advice? I have a fairly old hp laptop that is running windows 7. How can I purseade it to work? Thanks.