hi
Clamav itself isn't a bad antivirus program. I use it to scan windows
and linux machines and it usually comes up clean, but will catch
something bad if it does get onto a computer. Clamwin though I think
uses either an older version of clamav or a forked version and yeah it's
never been great. If you're determined to use windows I'd recommend
using either avast if it's still accessible or MSE, which you can
download for windows 7 and lower but comes with windows 10. If you're
willing to try linux you can boot a distro like sonar or vinux from a
flash drive, install clamav, run something like sudo freshclam to update
it, then scan the windows drive. It's not graphical, you'd need to run
it from a command line but it's an option.
Thanks
Kendell Clark