The default browser in 7 is the 32bit IE. You actually have to browse the Program Files not Program Files(x86) folder to the Internet Explorer sub folder there and create a new shortcut for the iexplorer.exe file to run the 64bit version.
The Adobe TechNote page explaining this and also pointing out the upcoming Flash Player 10.1 is seen at
Flash Player support on 64-bit operating systems
The prerelease of 10.1 however is available at
Adobe Labs - Downloads: Flash Player 10.1 Note the warning notice seen there first.
Quote:
Important: All users should uninstall any currently installed Flash Player before installing the latest prerelease.