Adobe Reader 8 or higher....

I keep on installing adobe, even though I had it already. The form I am trying to download says I need version 8 or higher and cannot open it. Can you help?

I cannot open reader., when I download the document I try it to open but it gives the message above... need version 8 or higher.... Apparently I had higher but it will not open either,.   Don't remember having this problem in the past.....

Advice given says open in acrobat but surely I have to download the document I need.... then I press on the downloaded document and then I have the problem.  so step by step please?