no you won't be safe.
Windows is known to always have backdoors some of them placed there intentionally by Microsoft itself. being closed source it will continue to have these weaknesses forever.
additionally anti viruses are not 100% reliable all the time not to mention that it may not even be possible to categorize certain things as virus/malware to be detected by them. for example a malicious altcoin wallet that searches your computer for your "bitcoin wallets" and sends them to the attacker is not doing anything detectable by an anti virus!