Portable apps do not install

Are you sure you aren't downloading the sf download page? None of the apps are

Something is messed up somewhere.

Do you have javascript turned off by some chance? SourceForge has an Ajax thingy on the download page, maybe that is the problem.

On the SourceForge download page, where it says "your download should begin shortly", do you just let it go? Did you try the bit where it says "if you are experiencing problems with the download please use this direct link"?

Just below that, there is the icon of the SourceForge mirror you are using. Below that is another little link that says "Select a different mirror?". That's where you select a different mirror. If you have javascript enabled, it gray's the page and lets you choose a different mirror.

I think you said you re-downloaded things, but to your USB drive. One of the suggestions was that you re-download to your local drive (e.g. your desktop). That's not just telling you to do the same thing yet again and expect a different outcome; downloading to C: is different from downloading to a USB drive. (Shouldn't be, but sometimes is.)

The PA installer is actually ".paf.exe". So, in particular, it is an .exe as well. That may seem obvious to you, but I can't tell, so I'm stating the obvious.

If you look at the Download Now button, you'll see that it states the size of the file. 7zip, for example, is 1.1MB. If you download it and the result is 22KB, you don't need to try to execute it; it's not the right size.

If you are right clicking on the "Download Now" button, it won't work; you need to follow that link to the SourceForge download page, where it will start downloading automatically. If you need to download it directly (I personally hate the things that start automatically, so I've done this), look for the "use this direct" link and right click on that. You could (for example) copy the "direct link" and use the result of that with WGET.

Good luck!

It's true.