If you'r pc is infected with virus or for some other reason you can not edit your registry you may see this kind of error. now if you clean your virus that won't fix your registry issue. You get stuck.
there is some free and paid tools that can fix it. but some time it is hard to find because there is too many tools that offer that support but which one is good or work is hard to find.
If there is a easy way that can fix that problem without any soft is better no need to carry any soft.