I installed N360 on our 3 PC’s. A FULL system scan on our ‘Vista’ machine takes about an hour. On our older ‘XP’ machine about 1.5 hours. On my most current ‘Win7’ PC the scan has been running now for, get this, 17 hours (with approx 1,470,000 files scanned thus far)!!! What is going on?! Thanks.