Mine was delivered with Windows 8.1.I upgraded to Windows 10, (which worked fine with the Lenovo, but I HATED the way it wrecked explorer, control panel, and my tiles, that I reverted back.)
The bad:
At over 14" tall and 6 inches wide and over 15" deep, it is a behemoth, and the case requires two turn screws to turn to open.
The worst.
You cannot add a video card without first altering a bios setting.
The Good:
It is quiet, both the fan and the hard drive
On the front panel there is a SDHC full size slot, two USB, and AUDIO (in and out)
DVD writer
The rear panel has about 5 more USB slots
The best
Very low price
Very reliable
I had purchased another low priced model from another VERY WELL KNOWN and REPUTABLE internet retailer 3 months before and bait and switched and had no recourse!Lesson learned.I stay with Amazon.