Script for finding processes

i just need a script that will run every hour and will pop up a message on screen
with the processes that use 50% of the cpu or memory. if there are some.

usually we do not write scripts or ready to use code on request. But you could try to find something what fits your requirements in the Powershell Gallery or in the Microsoft Technet Script Library.

Have you tried using Get-Process and Where-Object?