OK, then we seem to have a computer that can comfortably work with OM Lx 4.2.
I need to say that I am guessing at your knowledge level. So please do not be offended if I “over explain”. If I don’t or the how to article don’t explain well enough then please do ask us to do a better job of explaining. This process makes us better able to help other users. And I learn things in the process myself. I am approaching this as if you or anyone reading this has never installed an operating system before. You should not hesitate to use a translator to translate to your language (Portuguese I think) if you need to for clarity.
We have this how to describing how to install any current version of OpenMandriva Lx:
How to Install OpenMandriva Lx 4.3
Also read this:
OpenMandriva Lx 4.2 Release Notes
I recommend reading both of those and asking questions until you have a good general idea of what is involved in installing a computer operating system.
I would also recommend you start with breaking this in to easier steps rather than trying to do it all at once the first time. So first just focus on doing the first three steps in the how to install article. When you get to step 3 “Start OpenMandriva Lx live mode”. At that point you will not have changed anything on your computer yet but you can look around inside of a running OM Lx 4.2 system and see what it is like.
Note: I know the how to is titled “How to Install OpenMandriva Lx 4.3” but the how to will work for any current version of OpenMandriva Lx.