How can you fix a high CPU usage (100%)?

Well first off there is no “Windows 7.9”. 7.9 is the highest score you can get for your hardware on the “Windows 7 Experience BS-o-Meter” - which says theoretically you can run Windows 7 perfectly.

Second your issue of 100% CPU usage can be a pain to nail down. Lots of things can cause that to happen. The processes us listed that are using lots of CPU are supposed to be there. explore.exe is more or less your desktop and file browsing system. svchost runs a bunch of windows services in the background. And well firefox is your web browser. I would look at the svchost first, sometimes viruses get hidden in them. There are a lot of guides around for fixing svchost 100% CPU issues. Just Google svchost 100% CPU. But sadly 100% CPU usage can because by some many stupid things I can’t just say “Here is your problem.” Check your laptop’s temps. Laptop’s like to run hot and over heating can cause your CPU to run very efficiently and spike up to 100%. Software errors will sometimes cause other things to spike up to 100% CPU usage, making it hard to find the root cause.