I finally installed it through the "Update assistant" and there were no major problems during the installation (apart that I had to put the tablet near the wifi router to download the required files faster ) and everything is running fine. It also took around 2 hours.|
As a comment, at the beginning I had around 23 MB free in the hard disk and the installer told me that there was not enough space. After moving/deleting some files (until around 24 MB free), then there was enough space.
Since the last version of Windows is kept in the hard disk in case you want to return to it, now, after the installation, I have around 16 MB free. In some weeks I will "clean"/remove these files.