adobe reader 9

I have a new computer with windows vista installed. I have also downloaded and installed adobe reader 9. I have been trying to open a pdf file on a website but I keep getting the message that i need adobe reader 8 or 9 to open the file? Im not quite sure what i am doing wrong. I have checked my programs and I definately have number 9 installed so why would it still be coming up with this message and not opening the file? Any suggestions would be appreciated. Thanks.

Hi chrissy72.

Where did you download it from? Was it here: http://get.adobe.com/reader/otherversions/

If not, try it from there.