Probably not worth it. These tuners can often do more harm than good. I don't really trust Norton to do a good job any more - I have seen the damage that it can do trying to recover JPEG image files.
You can get the OS to show you these startup programs manually and decide for yourself if you need them or not. Create a restore point first in case you later regret your decisions and stop something you shouuldn't have done!
Probably nothing much there to write home about.
You can if you navigate to the holding area where Windows keeps its "temporary" files. You will be amazed at how many prehistoric orphaned files can lurk there on a machine that has been in use for a while.
It is worth purging the accumulated dross once in a while but only essential these days with such huge disks if you are in danger of running out of disk space (which is now quite a rare event).
Remember it is in their interest to make what is found sound as bad and frightening as possible. There is also a fair amount of similar dodgy ransomware out there using more or less the same sort of modus operandi!