My mac reset itself and i dont know what to do?

i went into the settings on my dads computer apple mac and i went into macuser/library/preferences and i think i accidentally dragged a file called library out of the folder. my question is would somebody be able to tell me if there is meant to be a folder in there called library or where all the folders called library are located?. this is really important because he is really angry. and the programs have reset themselves but everything is still on the computer
thanks very much, any help appretiatted

G'day and welcome to the forums. Shame it is under such duress for you.

There are two Library files, one under Computer which contains OS files, and one under Home which contains personal settings, screensavers, downloads, documents etc. Unless you know what you actually did , and it sounds like you have removed the Home file, Dad looks like being up for a complete system re-install, unless he has an external drive backed up with SuperDuper or similar.

Now you can understand why he is not a happy chappy.

There are at least 3 Library folders. The two mentioned above, and another one in the System Folder. There would be more if there are more users. Each user will have one. I don't know of any files named Library. I tried Spotlight, that worthless piece of dung, and it did not turn up any files, but, neither did it find any of the 3 Library folders.