Never had a virus in over twenty years, never have problems with any of my machines (I'm talking home machines, not the servers I support and most of the time it's because a drive died but since it's RAID 5 or 10 plus hot spare, I never see the problem except when the management software goes red and announces a dead drive, within four hours, I get a replacement. While the hot spare had already rebuilt itself and is running just fine).
Drive arrives, take 45 seconds to hot swap it and the drive rebuilds we go on, no problems. We also keep some spare hard drives just in case.
I've never bought a registry cleaner, let me guess, you get a pop up and it says you may have problems with your registry, your run their tool (scam) and low and behold, there numerous registry problems so you buy their 'tool' and it 'fixes' your registry, social engineering at its finest.
One more thing Windows 7 defrags automatically once a week though you could change the schedule. I just looked at my four partitions and everyone show zero percent fragmentation.
Windows is coming up with a new file system called. “Resilient file system”. It’s got great features but I would wait a while before changing from NTFS. It’s trying to be like ZFS but ZFS itself took a while to be reliable.