yes it will. though depending on when you activated your system you might have to call Microsoft to activate windows again after reinstall to a new hard drive though usually its painless and quick.
Does it sound like its going out or is S.M.A.R.T right in that its in good health
I was answering your last question.
any sound changes means somethings starting to fail. when does it make the sound? is it when its sitting idle, or when its activily reading and writing every single time or only when its reading and writing at specific times(kinda seems random)
usully a scratching sound means the hard drive heads are touching a platter but usully when that happens the smart values fail and it defently wouldn't pass the manufactures test due to all the metal shavings that would form on the read write heads. this leads me to believe a bearing has failed inside this would lead to more and more movement in the hard drive platter. if this is the case then you hear the noise but the platters are still spinning fairly level that's why its works ok but as the damg gets worse it will eventually fail. kinda hard to tell I know of drives that lasted with bad bearings for longer then a year and others that it caused it to fail within few mins.
the safest thing would be to get a new drive and clone your current hard drive over to the new one if you think the noise is bad enough that it would fail soon, then you wont have to go though a clean reinstall of everything. its your choice though you could just wait till it fails then do a clean install on the new drive (as you say you don't have anything you need on your current drive)