I’m curious to know how you found out it was SISZYD32.exe if your existing antivirus didn’t catch it.
It took care of the dll right off and led me disable siszyd32.
Somehow siszyd32 kept re-enabling itself and I knew that because Win Patrol Plus (Scottie) kept asking me if I would allow siszyd32 access my computer, repeatedly I said no.
That's when I began running other utilities, anti-virus, anti-malware, registry cleaner, everything got blocked in progress, usually when its process was coming to an end. Some had also detected the virus but the virus terminated them before action could be taken.