Registry is often called as the heart and soul of a computer system; it is because windows registry is a hierarchical database which stores configuration settings, applications – kernel, device drivers, services, SAM and various options on Microsoft windows operating system. Registry contains keys and values, in addition to which each key has a sub key.
Any complexity in windows registry can be disastrous and almost all problems which the system faces including slow performance, freezing, hanging, crashes, stop or blue screen of death errors are caused due to errors in registry. So it is indeed necessary to fix it, but since registry has complex entries as upper and lower filter, and some of them are root keys, manipulating registry is not possible until and unless you have complete information about role of each registry, which would not only be difficult but time consuming as well, still there is no surety for the registry to be repaired. A better alternative to this is windows registry repair software that efficiently scans the registry entry, detect and repair it too without modifying or in any way destroying registry entries.