If your Windows 8 system seems sluggish, the revamped Task Manager may be able to offer some clues. To open the Task Manager, simply Press 'Ctrl+Shift+Esc'. Now click on'More Details'. The simplified Processes tab then reveals what's currently using your CPU time, RAM, hard drive and network bandwidth. The more in-depth data available in previous Task Manager versions is now accessible in the Details tab.
The Performance tab gives you a graphical view of resource use over the last few seconds, while the App History dialog looks back over days or more to reveal which app is the most resource-hungry. Click on the new Startup tab to see programs your system is launching when Windows boots. The 'Startup Impact' now shows how much of an effect each of these has on your boot time. If you spot high impact programs you're sure you don't need, you can right-click on them and select 'Disable' to stop them from loading at startup.
If you'd rather use the old Task Manager, you can simply hold down the Windows key and press the R key. Type in 'TaskMGR' then press Enter.