We need to know what you did, meaning, did you try to load a special rom found on this site? Usually if the load failed then your system will not operate correctly. It is also possible that the tab is faulty. If you DID NOT load any roms or other programs to modify the tab then take it back and have it looked at.
If you did try to load a rom or other software then you will have to reload the OEM Rom (Original Equipment Manufacture). This can be found here
. The OEM Rom Firmware you will need is P5210XXUANB4 which is the firmware for Portugal.