I am giving my pc to my grand kids and want to give them a pc with just the factory settings and no info that i put on it over the years.

My computer is slow. My virtual memory always says its slow. I have a virus protector that i quarintine the bad stuff ever once and a while. I want to set it back to factory settings. Will that delete unneccessary stuff? and make it faster? Can i do this w/o deleting some program like word? and powerpoint? if not are there any tricks to making it faster!?

I recently did a Quick Restore, which put it back to factory settings because of problems I was encountering, but now I keep getting these same Pop ups from Messenger Service advertising all these different registry cleaners & saying if I dowload there product I wont receive anymore pop ups…they are popping up back to back & its getting frustrating!! Can someone tell me how to stop them from popping up…Help!!