Assuming that you mean Process Control Block (PCB) in a Windows environment. Well, to access the PCB you have to work on the kernel level. So, you'll have to download the Windows Driver Kit SDK as a starting point.
Next, you'll have to learn how the Process Control Block (PCB) sometimes referred to as the kernel process (KPROCESS) block, which is part of the EPROCESS block, and the process environment block (PEB), which is pointed to by the EPROCESS block, contain additional details about the process object.
The EPROCESS and KRPOCESS blocks are only accessible from kernel mode. Here you will have to install a kernel debugger tool (KD). The KD tool will allow you to inspect the KPROCESS (PCB) blocks.