Does anything happen ? any error message ?
I had a case recently where the Path used was not writeable
> Have a bit of a problem opening pdf documents in windows (save to a path and automatically open)
No error at all! had a few problems where it turned out there were no records so it didnt save the empty pdf which made sense but for some reason it exports it to the temp folder and does nothing on one computer, but it works on another computer! And you can even go into the temporary path and open it manually
On the Problem computer, if you double click on the PDF does it open in the correct program? It sounds like the association between Adobe and the PDF has been broken? You might try re-installing Adobe and see if this resolves the problem.