I want to block a certain program from running like "Keyboard Collector", a key logger which cannot be seen running in the task manager but active and running, or any kinds of program similar to keyboard collector.

How to code this kind of function? If its OK, may you post the solution in this thread? Thanks in advance :D

Everything has a visible process somewhere - even if it's being hosted by another process i.e. svchost.

What you need to do is find out where exactly the keylogger is located on disk - or figure out how it is starting up.

If it has installed itself as a service then you will need to stop the service that is running it - disable the service or simply delete the assembly.

If it is starting with the registry start up software you need to go into the console and start up "MSCONFIG" in order to edit the start-up keys.

Otherwise it may be in the user start-up folder - if it's there just delete it.

When I install Keyboard Collector, it resides in the Program Files,.(It is only a trial version though)

I want to code an application in C# where it can negate the Keyboard Collector from running without deleting it. It will only show a Message Box saying that Keyboard Collector has been stopped at the same time it is blocking the said program. Like what anti-virus are doing..maybe

To get the kind of functionality that anti-virus software is using I believe you are going to need to write some kind of service.

I won't be able to help you out with that but suggest doing some research online about how anti-virus software works. - this is not common functionality.