Process that takes up lot of resources on a windows box is a pain that can be avoided at times. There are tools available to monitor the running processes, giving us an option to kill them if they misbehave, or at least lower their priority.
Process Hacker is one such free tool with tons of features to manage the processes. It is an Open Source tool, released under GPL. It has features to monitor processes, service, and network. A tree structure shows the entire hierarchy of the running processes, giving a lot of understanding to the user as to how the processes are being run and which process is child to which process. Users have an option to change the priority of the running tasks, force terminate the threads, free or de-commit memory and a lot more. There is option to create new services as well from the UI.
Process Explorer, offered freely by Microsoft is another such tool, with similar interface as Process Hacker. It shows you detailed information about a process including its icon, command-line, full image path, memory statistics, user account, security attributes, and more. It however does not offer network monitoring as Process Hacker does, but given that it is available from Microsoft, it enjoys its fair share of popularity amongst Windows Administrators.
Process Lasso is a process priority optimizer for Windows. It gives immense control over running processes like set processes exclusion, disallow programs from running, assigning CPUs to a process, Instance Count Limits, and a lot more. It comes in two versions, free and paid. Paid version has added features like Process Watchdog, CPU throttling etc. It is much advanced than both Process Hacker and Process Explorer, and requires users to have a proper understanding of what they are doing or want to do.
System Explorer is yet another free task manager alternative, giving information and control over CPU, memory, network usage and other internals. It is available in multiple languages, and has a portable version available as well. It offers nearly the same set of features as Process Explorer. It is a basic tool when compared to the ones described above, and can be used effectively in small environment like on your home PC.
Faithful old Task Manager always comes handy when everything else fails, or when there is no other alternative (like in Office/Schools). Though not as advanced as the ones described above, it offer a basic set of features to monitor running tasks, CPU, services, network and memory. Since it comes built-in with Windows, it is obviously the most used process manager, though not the most powerful.