I'll try keep it slightly less technical and more "English".... :)
A process is a piece of software that runs on your system which is designed to perform a certain set of tasks. If a process has no work to do, it will still run on your computer waiting for instructions on what to do next. Each process is given a PID (Process Identifier) by the operating system which is just a numeric identifer and can be different each time the process starts. Having a PID helps the computer differentiate between processes with the same name. Look in Task Manager and you'll see several processes called "svchost.exe". Each of these has its own PID, otherwise the computer would not know which "svchost.exe" it should be talking to.
When a process receives an instruction to go do some work, it will create a thread. A thread is a communication mechanism between the process and whatever comonents it needs to get in touch with to carry out the work. A process will open a thread so that it can send the instructions needed to carry out the work down that thread. Responses come back and when all work is completed, the process often closes off the thread again because all instructions needed to complete that set of tasks have completed.
A handle is way for a process to "reserve" resources for a process to ensure the process is not ignored and gets a response.
May make more sense in an example:
1 - You install AntiVirus software and the AV process starts up and runs on your computer. It is given a PID just in case there is another process using the same name.
2 - You tell your computer to run an anti-virus scan. The AV process will open (at least one) thread so that it can send instructions because it now has some work to do.
3 - The AV software sends an "open handle" request to your harddrive using the thread it created. A handle is opened to your drive so that the "scan files for virus" command coming from the AV process can be run on the drive.
4 - The AV scan completes on your computer. The AV process receives information saying "AV scan on this drive is completed and all is OK". The handle is closed because the AV process no longer needs access to the disk. The thread is closed because the AV scan has competed.
Commit Charge is just the sum of the available physical and virtual memory.
Hope this makes sense??
Very good question by the way!! 8o)