My new computer came with NIS 2010 preinstalled on a 60 day free trial. Only 2 days to go and I was going to subscribe online but have managed to buy NIS 2010 Performance Pack (which includes the full version of Norton Utilities) from a shop cheaper than online subscription. Should I uninstall the, presumably oem, version first or can I just put the discs in from the version I purchased and will they overwrite the preinstalled version?