Some thoughts and suggestions
I'd like to preface my (most likely LONG) post by saying, I realize you're frustrated. And you would like to resolve your issues as quickly as possible. You also stated you're 'new at this'.
I'm a bit frustrated myself. Perhaps, I was unclear in my initial post. After asking the (unanswered) question, if those were the ONLY 3 programs you were unable to open, I followed with "Under certain circumstances the System File Checker (sfc /scannow) might help. While other's, running the Rkill tool might do the job."
More than anything else I was attempting to learn YOUR "set of circumstances". Sorry, if I was unclear.
For example, had you answered the above mentioned question, it might have helped tailor a response. It's not uncommon for malware to target executables and alter their file associations. It's unlikely to be your case if all but 3 work. And none of the programs were A/V or A/S related. (See this) I'm using it as an example as to why details and information are important.
Can I also assume you made sure (backups) what you couldn't afford to lose was safe, as Bob suggested to be your first step? (After the fact, backups are likely to include the malware as well. Although, there is a way of saving data) I only ask because your immediate response was "How do I do SFC?".
I felt it was important to rule out malware, PRIOR to proceeding further. It's frustrating on my end, with bits and pieces offered. AGAIN. I realize you're new at this. And also frustrated. My goal is only to try to help. Not to point out the error of you ways.
After you make sure all prior A/V's are (cleanly) uninstalled, I would then suggest utilizing the Rkill tool (immediately) followed by scanning with some of the tools Grif includes in his set of instructions.
Best of luck..