I have just purchased McAfee virus scan and now i have installed it i was wondering if i were to "sale" it to my girlfriend and put it on her pc, would mcafee know it was on two pc's or wouldn't it matter???
Gaz 25 is right. Ideally, the secondhand & 'used' software being sold on Amazon, are genuine & have been uninstalled from the seller's PC before sale. If it isn't then it would be as you say - 'contributing to illegal reproduction of the software'.
If you're still unsure, the best thing would be to contact McAfee directly & ask them what you've asked us. They would be in the best position to answer you (though, I doubt their reply would be much different from my initial posting). HTH, G
My own experience: Sometime ago I purchased a genuine copy of Norton SystemWorks. A while later, when I found I wasn't really using it much, decided to sell it (on Amazon). Not being sure at the time, I asked Symantec if I could do so & this is what they had to say, "In order to remove your registration you have to uninstall the product from your computer and passing it on to someone else, they will have to re-register it upon reinstallation." (I'm not quite sure why they used 'passing it on' - probably not exactly 'legal' to sell it on either!)