How did you download and install the game? What are your system specs? Is that "it keeps saying corrupt file" the message you get when running the installation file?
There are three ways to download a game.
1. Direct download via browser.
2. Using the
GOG Downloader.
3. Using the
GOG Galaxy client.
The first two will get you an installer file you then have to run manually to install the game, GOG Galaxy let's you automatically install a game.
I'd download the game again, using a different way than the one you used the first time. I'm still using the GOG Downloader which, while no longer officially supported, works very well for me.
Assuming you got
realMyst, the MD5 checksum is MD5: 4F70A1C4EDF287B240338BAD3397BBE7
If you're doing a manual installation, you may also want to make sure all traces of the previous installation are wiped before.
Also note that Win 7 and Win 10 are not officially supported.
Lastly, you may want to take a look in the
Myst series forum.