My Computer problems.. My computer's window is a xp, it had worked well when i bought it, but now,

Question

My computer's window is a xp, it had worked well when i bought it, but now, after I plug another hard drive, some folders icons were black and I also can not open them. They can not erased from my computer and for me it like a Virus, that if I deletes one of them, it could restores on it's own.