Thanks Ed for your answer.
Indeed, it has a MBR, and a partition.
But, erasing the partition and the MBR, it doesn´t show up in windows explorer. And the only way that i know to solve this, is going to “administrative tools” and assign a letter to the unit and it shows up. But of course, first windows ask to add MBR or GPT, create a partition and format it.
The drive, still works fine reading and writing data.
Using it in windows 7, as a fixed drive, it has no trouble to remove it, but in windows XP, It cannot be remove safetly. So I´m interested in returning it´s “removable” setting.
I used the flash drive in 5 computers (windows 7 and XP), and in all the drive shows up as a fixed disk.