Hi Alex,
Unfortunately there is no way to make Gmail your default email in Windows - Gmail is a service rather than an application you can set as your default.
Depending on how you want to set things up, however, there are a couple of options:
- You can set your web browser to open up Gmail when you click on email address links
- You can add your Gmail account to an email client (such as Thunderbird) and use that to send and receive emails
If you want to continue using Gmail's web interface, I recommend the first option. If not, go with the second option. Let me know which one is for you and I'll guide you through the process.