I have the exact same model myself as my work machine. It's not the fastest PC in the world. I happened to coincidentally be copying a folder when I read your message, and checked the processor usage in the Task Manager. It was averaging 18 to 20% usage. So 100% is definitely excessive.
There are numerous reasons why there may be high processor load when doing a copy operation and nothing else. These can include:
- transferring data between two different drives / storage devices
- checks of the data being performed by virus prevention software
- a background process (a file, not a full program) that is running
Are you copying to another drive, or do you have antivirus software installed?
I did further research with the search term 'cpu load 100% when opening browser'. It seems a lot of people have this problem with CPU load when their browser (Chrome in particular) is open. Most people offering advice assumed it was caused by a virus or malware, but it was occurring for some people even with a clean install of their computer.
Other than viruses, another cause suggested was resource-hungry browser extensions, or the Flash / Shockwave browser plugin. Since you get the CPU load when doing other activities such as file copying and opening folders though, that would seem to reduce the likelihood of browser extensions being the cause unless they are being loaded in and running automatically when your PC starts up even when the browser is closed.
It is one of those frustrating situations where some suggested solutions work for some people but not for others. What is the memory consumption like during the slowdown? If memory becomes low then the computer may try to use the hard disk as a form of virtual memory. This frequent hard drive access is known as 'disk thrashing' and can cause slowdown.