Can I use a single Norton 360 license (3 PCs) on the same computer 3 times?

No. A single Norton 360 license can be used on a computer only once for the duration of its subscription which can be for 1, 2, or 3 years (2 and 3 years subscriptions are not available in all markets/regions). Note that a subscription period starts as soon as the software is installed and activated on the first PC.