first is this a generic oEM version or is it a "dell", or other branded OEM Version
If generic OEM then you would have to delete from old system, or pull old HDD and put in new system (still requires a re-install., from there it's a 50/50 on whether you have to call uSoft. Although not totally ethical, they may be in a good mood. If you are "pitching" the old system - it died verses being unhappy. If you are selling your old system, then yes you should by a new copy.