I downloaded one but it just told me I had problems and wanted me to pay to fix, are there any reliable free ones or can I clean the registry myself? (links would be appreciated)

I found regedit on %windows%. i opened it and i go to hklm\software. I accidentaly deleted the keys in there. whenever i open a program, there is always error and crash to desktop. Please help me.

Basically for overall PC maintenance & optimization.
Which is the best for free version:
And which is the best for a paid version?
What do you think of this software called ‘PC Optimizer Pro’?

PC Optimizer Pro

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