It has Win 7 and came with a Win 8.1 Pro recovery disc.Also, you can upgrade the Win 7 pro or 8.1 pro to Win 10 for free at this time.Right away I disconnected the 2TB HD and installed in a 240GB SSD.I used the recovery disc to install windows 8.1, now it boots in 15sec.You will need to reinstall some drivers after you do this.After this I reconnected the 2TB HD (this requires a Sata III cable), the system still boots from the SSD, I didn't need to enter the BIOS.I bought the system for $849 and noticed the price dropped to $799, so I asked Amazon for a partial refund using its online chat, it only took 3min. You can do this for any product fulfilled by Amazon if you find out the price dropped, be it within 7 days.