Can I uncompress files that Windows Disk Cleanup compressed?

Factual Questions
1

Someone ran Disk Cleanup on my Windows XP system and checked the box for Compress Old Files.
Absurdly, this “compressed” a lot of program files, so I assume they now they get uncompressed every time I run applications.

At any rate, is there some way to get them all back to normal ?

2

I haven’t tried it personally, but here are some instructions.

3

Select all the files you want to decompress. Right click > Properties. Click the advanced button. Now unclick the option to compress. Press OK.

4

Thanks. My searches always ended up talking about Zip files.