I had Acrobat Reader 5.0 that came with my computer. I downloaded Adobe Reader 7.0 from Internet and uninstalled 5.0. Later I found I could not open pdf file on internet (files on comp. opens). When I open on intrnet pdf files, it says done but the file is completely empty.

Try opening other PDF files.
Acrobat 5.0 works with the newer versions.
You and akways uninstall and re-install.

Thats because Acrobat reader 7.0 is a larger file than Acrobat 5.0 and takes longer time to load. And if the computer is not fast enough, Internet explorer can't start the Acrobat reader automatically. So when u want to open any pdf file on the internet, First open adobe acrobat manually and then open in internet explorer. Hope it solves ur problem

you most probably uninstalled V5 after installing V7

If so, uninstall V7 and install it again, it will solve your problem.

check the following:

Open Adobe Acrobat Reader and click Edit, Preferences. Choose Internet in the Preferences /Options window. Uncheck Display PDF in browser option and close the dialog. Repeat the same and this time, enable the Display PDF in browser option.

cheers