Removing Adobe Acrobat reader 5.0, and installing newer 7.0.9 version

My IMAC with Panther 10.3.9 has Acrobat reader 5.0. This appears in Finder>Applications>Adobe Acrobat reader 5.0 folder. I find that the lastest version of the reader for my system is 7.0.9, per Adobe's website in the reader download section. I downloaded version 7.0.9, which appeared to have occurred without problems. When I went back to Applications>Adobe Acrobat reader 5.0 folder, the folder still indicated 5.0, not 7.0.9. Not convinced 7.0.9 was actually implemented, I moved the Adobe Acrobat 5.0 folder from Applications to Trash. And yes I emptied the trash. I then downloaded 7.0.9 from Adobe's website again. The download again appeared to have occurred correctly. There is no sign of Adobe Acrobat reader 7.0.9 in Applications, nor is the 5.0 folder there since I put it in trash. Why did I want to upgrade the reader version in the first place? Some PDF files that I tried to download wouldn't. This is the first time that I have encountered PDF files that would not download in readable format. The PDF help section of the website indicated I needed the lastest version of Acrobat reader to successfully download the PDF files. Since I did have an older version, the version upgrade was attempted. Where do I go from here?

IMAC G4 Mac OS X (10.3.9)

IMAC G4