Amberly,
It isn't clear what you're trying to do...are you wanting to try out PS7 or are you wanting to update the retail PS7 to the current version 7.01? The link you provided is strictly for downloading the demo version. While I've never used the demo, if you have been using it, found that it wouldn't open again, and are trying to download and install it yet one more time, then I'm guessing the demo is time-limited and your tryout period is over. Reinstalling may not do any good, if the demo placed a time-tagged piece of data on your PC that it looks for on any reinstall attempt.
If you're wanting to update a retail copy of PS7 to 7.01, then yes, you're downloading the wrong thing and need to go to <
http://www.adobe.com/products/photoshop/update.html>
Hope that helps,
Daryl