|Run your AV's because viruses can cause slow downs. Also install, update and run MalwareBytes freebie because this sometimes finds and fixes what AV's miss.|
Try CCleaner - it cleans out a lot of junk safely.
Everything next to the clock is a running process.
Uninstall any programs you don't need that run in the background.
Type msconfig in the Run box and look in the Startup tab. There may be some items you can untick if you are not using them.
Please come back and let us know how you got on.