If suddenly some of the .DLL files on your computer get size of ZERO (0 bytes) and you are getting “Bad image (0xC000020)” error preventing applications from running, it is most likely your McAfee antivirus that is doing the destruction to the DLLs on your computer, see similar reports from other softwares https://jira.phoenixviewer.com/browse/FIRE-21578
Really, most antiviruses do nothing but slow down your system and do not really offer any protection for new threats (despite vendor claims). Use Microsoft built-in antivirus. It is as good1 as any others, but at least does not destroy your files. As for safety - simply backup your computer periodically, don’t open suspected attachments, don’t use cracks, don’t visit illegal sites, don’t use public free WiFi and isolate your computer from the outside using NAT router/firewall. As simple as that.
1As good as does not mean that it will protect you everytime. It means that it will protect you from OLD threats as any other antivirus. No antivirus is able to protect against newly released virus. Your best line of defense is: full system image backup done periodically (say weekly). In case of new threat you can always restore your computer from full system image backup.