|mickliq clearly said copy all your data... not the Registry, not the OS, etc. Heed his advice after you read it more closely. |
There is no software that can accurately guess where, what, when, how you have saved your data. You ought to know what you want saved and where it is stored. Back it up.
On the other hand, formatting is not a smart solution to the problem at hand. Un-installing iTunes and all related modules and then re-installing might get you closer to the desired results.
... if the "...some softwares by which itunes could not work..." event[s] were fairly recent, a System Restore to a prior date could possibly rescue you from your self-inflicted dilemma.