I don’t recommend downloading inferior, free antivirus software, so you can imagine what I would say about having absolutely no antivirus software at all. You really must buy antivirus software. If you don’t, you can and will be infected, and those infections can and will harm or even destroy your computer’s performance… it may not happen today, tomorrow, next week, or even next month, but at some point it will happen. If you don’t protect yourself, then you must be willing to accept the consequences of losing all the programs and files that you likely have spent a lot of time and money acquiring.