I have a HDD with 4 partitions, and I want to format only one... the one used for uploading/downloading stuff (torrents and so on), so it obviously has no OS on it. My concern is that it may become unusable if I just click Format in the right click menu in my computer. I'm guessing it has some bad sectors, due to high usage in the last monthsm because it keeps interrupting when downloading and it keeps giving me the cyclic redundancy check. So, can I do that? Or what software should I use?

You can only format one partition at a time. As long as the format command is on a different partition (the OS partition) you can safely reformat the partition.

Thanks Scott, I apreciate your answer!