My Minecraft won’t open!

Ok, so my friend downloaded OptiFine for 1.13.2. While downloading it, he clicked on an ad instead of the actual download and got a virus. His antivirus took care of the virus and everything was fine until I’ve tried opening Minecraft and it would just get stuck on the Mojang loading screen.

He deleted OptiFine and tried opening Minecraft again but it would just keep getting stuck on the loading screen. If anyone can help, I would really appreciate it since I feel really bad for my friend since he loves Minecraft.

Suggested solution: Check the integrity of the Minecraft files. Some files may be misplaced or deleted – reinstall if needed.