ROUND ROCK, Texas--(BUSINESS WIRE)--Dell customers will be among the first to experience Windows 10, Microsoft’s best operating system yet, when it launches tomorrow. For those who purchased Windows 10-based devices during Dell’s pre-sale period, systems will start shipping today with free next-business-day delivery.1 Today, nearly 70 configurations of laptops and 2-in-1s and desktops and all-in-ones featuring Windows 10 are available on Dell.com and 51 Dell systems will be available from leadi