My Mac has been running slow and I opened up Activity Monitor, but I don't know what applications I can quit. I took a screenshot, can you tell me what I don't need? Thanks.
Those all look like system processes. A few questions:
How much RAM?
What model computer?
What processor speed?
What size hard drive and how much is free?
You could try quitting Activity Monitor, as well as that pesky Finder. Mine won't go away!