What to do if a malicious file keeps coming back?

I recently installed the free version of Bitdefender because I noticed my computer running slowly after I executed a setup file that would have supposedly fixed a problem I was having. It didn't seem to do anything except open up Windows Powershell multiple times, use it to execute something that was too fast to see, then nothing. I immediately knew it was a virus and knew I messed up because I really wanted the problem fixed as soon as possible. The solution looked legitimate, too. Anyway, for about a day now, Bitdefender did identify the culprit: 29834.exe, or, if using its full name (I believe), MSILHeracles.29834. It only shows up as 29834.exe though. The problem is, Bitdefender keeps disinfecting it, and the file keeps coming back. How do I stop the virus so I no longer get the notifications and so it's truly gone for good? Please help!