This is an easy one...when taking it from them ask about data recovery or anything to be saved, if they do or don't mention that it is possible IF a reload is required that programs will need to be re-installed, also at this time explain that you will remove programs such as Norton, when they mention they paid for it just say to them what others have above. Once you mention they brought it in infected with Norton or whatever so leaving it on the system won't help much, never been an issue.
