You can buy them from microsoft, newegg, amazon or any reputable local retailer, just dont buy the OEM editions. You should be able to reuse them on the same PC, however I dont think you can get any copies that can be used on multiple systems at once.
You can buy them from microsoft, newegg, amazon or any reputable local retailer, just dont buy the OEM editions. You should be able to reuse them on the same PC, however I dont think you can get any copies that can be used on multiple systems at once.