Reformatting is always the last resort because it creates a huge setback, potentially setting you month or even years behind in critical updates. You lose all your data and all your installed programs. Plus, you don't learn what caused the problem in order to prevent recurrence and finally, it may not fix it.
See the 3rd option
here.
I am concerned that you said your scans revealed several pieces of malware. While most malware can be safely removed, there is often collateral damage not repaired once cleaned. Do you remember what your scans found?