The problem of CPU getting slow and showing 100 percent usage is common and has been experienced by almost every one.
If same is the case with you then this is what you should do.
1. First of all find the cause and try removing it.Various causes are:
- Infinite Looping: Infinite looping occurs when a computer program crashes but is unable to shutdown
- Programs requiring large memory to run
2. The problem can be caused by spoolsv.exe, if this is the case then do the following:
- Open Windows Explorer, locate C:\WINDOWS\system32\spool\ and delete “PRINTERS” subfolder
- Type services.msc in the Run box.
- Click on “Print Spooler” service in the right pane and restart it.
- The service can also be disabled if you do not use the printer.
Most probably the CPU will not show 100 % usage again.