No? Please, read why you should choose Ubuntu. If YES, let's take the first steps in fresh installed free OS.
First of all, you need to update your system. After first update, whenever you take it, you'll have complitely fresh apps. First time, you'll get notification about available updates. Click on it and it takes you step by step through the process. Anyway, app for that purpose is Software Updater. Launch it anytime, and it'll check if there are available updates for your system.
Actualy, the program is set to check for updates every day. So, don't worry, Ubuntu does important jobs for you. You can change this and other options, but some other time about that.
After this step, you'll probably want to install proprietary graphics drivers. Am I right? Launch Additional Drivers program and choose relevant or desired driver for your graphic card.
Now you can play your favourite video games via Steam. Done.
Yes, that's it. Think about wireless driver - check it. It works. Sound? Works, too. Want to watch videos on Youtube? Go a head. It works out of the box. Flash plugin is there. I don't remember if I told you, but Ubuntu is fully equipped operating system. Everything, or almost everything works out of the box.