Windows slows down when you run too many application
Improve the speed of windows to run applications, games that require higher RAM by increasing your PC RAM virtually
Right click on My computer > Properties
On the right side the the pop up window
click Advanced system settings > Advanced > Performance - Settings
click Advanced > Virtual Memory - Change
Uncheck Automatically manage paging file size for all drives
click Custom size:
Initial size (MB): Use the recommended size given under Total paging file size for all drives
Maximum size (MB): Use twice the recommended size
click Set > Ok
Click Ok on all the opened windows
Restart your computer to apply these changes