Express Project is a compact and free project management tool.
The program arrives as a tiny 209KB download. We expected this to be a downloader, but no - it turns out to be the entire program, which of course installs in a flash, and is entirely adware-free.
As you might expect, this also means Express Project is extremely basic. You're able to define simple tasks, with dependencies. There's limited scheduling, and of course you can factor in your use of resources (though these are only text labels), and dependencies.
Still, if you're familiar with the basics of project management then you'll have mastered all this within about five minutes (at most), and the program can handle the core features you need. You're able to create tasks, assign and manage resources, understand task dependencies and constraints, schedule tasks automatically via critical path, and of course view a Gantt chart on demand to show your project status.