Can't open R files

Hello.  I'm not sure whether this is strictly the right forum but here goes...   I have got a new (well reconditioned) laptop and have installed R studio on it.  That works fine if I say write a little prog directly into it or paste R script from a word doc.  But if I try to open an R prog (which I've written elsewhere, the laptop doesn't recognise it as an R prog.  Instead it gives me a little icon with a pair of binoculars and says to try to find an app for opening said file.

But up to now I can't find anything on the net which will open the R files in the same way as they simply do on my desktop or old laptop.

I'd be grateful for any ideas or pointers 

Thanks

Nick Wray