- Disable Windows defender.
- Disable the windows indexing service.
I don't need the indexing service offered by Windows. The indexer hogs so much resource and I have not used the search feature much. You can easily disable indexing by right clicking on the drive in Windows Explorer and un-checking the indexing for that drive. Make sure that change is applied on the drive and all the files and directories under that drive. You can read more about this here.
Another worthy exercise is to launch msconfig and inspect all the programs that are started during start up. You can read more about how to do this here.
If you still experience slow down, launch the Process Explorer and inspect which process is taking more CPU. You can press space bar and pause screen refresh and inspect all the processes that are running.