I do not understand the following options in windows. Could any one explain
CPU Usage is how much your processor is running; of the available cycles to compute, how many are actually being used. On the left it shows the current value, and on the right it shows your history. The two graphs are because you have two CPUs (well, two cores in one CPU.)
Page File is something used when your RAM is filled up. All the data in your computer, while it's being used by a program, has to be "kept alive" somewhere, and this is what RAM is built for. When that's full, though, Windows will start using your hard drive instead. This is much, much slower to access than RAM, and will wear out your hard drive somewhat more quickly. I might recommend adding more RAM or closing unneeded processes.
In "Totals" you see: - Handles, which is resources that a program is using - for instance, a program might have on handle to keep track of a file, one handle to check your registry for settings, and many many others. - Threads, which is one part of a program that can run by itself. For instance, a simple video game will usually contain at least one thread for running the game, one thread for drawing graphics, and one thread to pay attention to mouse clicks or button presses. - Processes, which is generally speaking "programs". Some programs, like Google Chrome or Metasploit, will keep many processes open at a time. Each process corresponds to one .exe file, although several instances of the same file could be loaded as separate processes. If you change tabs in Task Manager, you can see a list of all processes, and how much they're each using up resources on your computer.
The other three boxes, "Physical Memory", "Commit Charge", and "Kernel Memory", refer to different parts of RAM & Page File. - Physical Memory refers to actual RAM (not page file!) being used by anything; right now you have 1.52GB out of 3.14GB of RAM available. - Commit Charge refers to Physical Memory and Page File, collectively. Right now you are using 1.77GB, out of a total possible of 5.07GB. - Kernel Memory refers to memory being used by Windows itself, and not by any particular process. Unlike closing a program, which frees its memory, kernel memory is almost impossible to free up.