Just because you have antivirus software installed on your PC doesn't mean a zero-day Trojan can't steal your personal data.
I recently decided it was time to retire TrueCrypt which I still used under Windows 10 with Full Drive Encryption (Works okay mostly, legacy boot only, needs to be disabled for each major update).
There are several obvious, basic steps to securing a computer: Keep it current with the latest operating system and application updates; ensure you've installed the latest anti-spyware and anti-virus ...