Help me with adding noise source in pspice

[sagh]

I want to simulate a circuit in pcpice Orcad 9.2. before simulating, I assemble my it in soldress breadboard. when I
regulate offset voltage point to get to zero volt I have oscillation. I want to see oscillation in pspice, too. So I want to
inset noise source into voltage source. I don't know how can I do that. Is there anyone to tell me what should I do?