How to delete Temp file in windows 7 and 8

Every one use windows now a days,when we use windows after some time its speed or we can say performance is very bad so here we can do simple steps just follow the steps.

1. Open run with the short key "Window key + R" 
2.  Now just type %temp% and then enter 
3. now delete the extra all file and there will be some file which will be not delete just leave it