How do i install software on windows 7?

i recently bought a new laptop at best buy and it has like all these programs in it that ive never heard of or ever want to use like the ebay shortcut, something called snapfish,all this hp stuff like games and movies, blio and all this other stuff i dont know like NCH software suite and streaming audio server that im afraid to delete because i dont know how important they are. i also have another question on what antivirus to decide, avg pro or microsoft security essentials