Existe uma maneira de não ter que colocar o Ubuntu em um disco ou USB?
Is there a way to not have to put ubuntu on to a disc or USB?
You can use Wubi, the Windows Ubuntu installer.
It lets you to install Ubuntu alongside windows without a CD or USB. See the WubiGuide if you want more information.
Another alternative (although a bit of a "chicken and egg" problem) is to install through the network. See a complete tutorial for building a PXE install server here:
Of course that assumes you have an Ubuntu server running, which I guess kinda defeats your purpose.
Perhaps if you give some details about why you can't (or don't want to) use either USB or CD to install, someone can suggest a solution that can solve your particular problem.