Modern drives are generally very quiet, so if you hear excessive chugging there is a problem, but unless the noise is rattly I doubt that it is a hardware one. My suspicion is that the backup restoration hasn't gone quite right. I'm not sure from your description if the backup is of the primary drive with Windows, or the seconadary drive with your saved files. If it is the primary, then I would prefer to see a clean reinstall. If it is the secondary with the saved files, I think your applications may be looking in the wrong place for the data, and hence generating a lot of hard drive activity in the search..