My computer is not very responsive seems sluggish, what to do
Sometimes you may experience slowness with your work/home computer and IT will find typically that one particular program can be the culprit, often we would advise users to close all open programs (Word, Excel, Skype, Outlook etc.) if possible and then if the problem remains a restart normally suffices. You may also find that for example you close a program such as your internet browser but it will still be running hidden from view, you will only be able to close these programs from task manager. This will often free your system resources and return your computer into its normal working state.
However we can appreciate a restart can be frustrating, obviously at home you don’t have an IT department and at times and a restart plus the inconvenience of the constant nagging of Windows updates being installed or pending status can cause a serious interruption, so for that reason I am providing additional information on diagnosing your computer issues. Hopefully with this information you can fix the issue without major interruption!
Utilizing task manager is the easier way to identify a problem process, this can be accessed by pressing Ctrl+Alt+Delete (you must be an administrator to your local computer to have access to this process), you will generally not have this access on a server (if you do, please contact your system administrator, who may turn red in the face). A word of warning if you do close any tasks try and make sure you always know for certain what they you are closing before you do so. If the process is a “SYSTEM” user task then I would mostly likely advise you leave them alone. Please be aware Anti-Virus, malware protection and backup programs will often use a higher percentage of your systems resources when they are scanning or updating (this is normal, but you may consider scheduling these processes for times you are not using your computer).
The 2nd Tab in task manager 
shows a list of processes, normally I would expect to see CPU usage below 60% (I make this approximation without any knowledge of your system spec or the age of your computer, so only use it as a guide), sometimes it goes higher but I would not expect it to happen over a long time unless your system is suffering with unusual slowness or is older.
Please note task manager is slightly different in Windows 8 and Windows 10, where the system and user processes are separated into a separate tab, in this scenario you would select the “Users” tab.
The System idle process identifies the percentage (top row) of CPU available to still use. You can order tasks by CPU as shown above with the underline, the underlined detail at the bottom shows the current CPU Usage overall.
If you highlight the problem process and select “end process”, you will then receive a confirmation to close the application, be sure you save any work before you attempt this, if you are unsure and are not comfortable doing this, seek someone with better computer knowledge.
You can also see how much of your system memory is being used by looking at the detail that has been highlighted (42% in this example). Showing a problematic process during regular slowdowns will help diagnose the issue more clearly.
The yellow highlighted area details the system memory usage (RAM), the physical memory works a bit differently from CPU and some processes will hog all of your system memory but it will not slow down your computer unless your entire memory is being used, if you do identify a process that is using 200,000kb+ (200mb) then I would imagine this process will be stealing unnecessary memory from other processes (programs such as games will use a lot of memory), this is not a worry unless your total physical memory usage is at 100% or near full usage. Processes such as databases will tend to use a lot more memory than anything else.