Hi, I have just bought a sandisk memory stick - 16gb - and I noticed that there is sth installed on it, clucbsandisk or something like that. I wonder, what is it, do I have to keep it, can I get rid of it without compromising my memory stick?

A lot of usb memory sticks come with some sort of encryption tools installed on them. Myself, I just reformat the entire device because most of that cruft is worthless. If you need to encrypt your data on the device, there are good full-disc encryption tools out there, including open source ones.