I bought the refurbished computer to replace a back-up computer which had a Windows XP operating system and gone out of order. The computer came with Windows 7 Professional. I had no problem in upgrading it to Windows 10 Professional. With its 8 GB RAM, the computer runs fast to my satisfaction. One glitch was that its optical drive failed to read new disks. Upon my report of the glitch by e-mail, the supplier immediately sent over a replacement. Replacing the optical drive was easy. The computer works as well as my primary desk top, Dell Inspiron 660s.