Can I log onto my mac g4 without a username or password?

I got a mac G4, and I lost the password and username. How can I login without it? Is there any way to login?

You will probably have to contact someone in support. Here is the website: http://www.apple.com...

Call 1-800-275-2273 for technical assistance

You can usually retrieve a password with the username , but you've lost both so the best thing to do is ask a professional. Hopefully you won't loose all of your files and programs.