Slow pc. i juz wanted to ask a question if isnt it ok for my pc if ill download Anti-spyware /

Question

i juz wanted to ask a question if isnt it ok for my pc if ill download Anti-spyware / Anti-Adware program,Anti-virus,and a Firewall coming from a deffernt sources at the same time? pls help because i bet my pc has a lot of viruses in it that causes to slow down the system. maybe could you giv me an advice on how to speed it up. ive deleted a lot of installed programs like antivirus and i wanted to dowload another. help its kinda confusing...