Instruction: Extract the value of the target attribute from the given product information and output it along with the corresponding source.

Input:
Product title: HP Pavilion 500-291 Desktop (Windows 7 Pro) (Discontinued by Manufacturer)
Product description: HP Pavilion 500-291 PC Powerful expansion With convenient expandability options, the HP Pavilion500 is the versatile PC that will grow as your needs do. With its clean modern style, it'll fit seamlessly anywhere you put it. With fast processors, strong graphics, and more storage, you've found your idealPC. With a clean modern style, the HP Pavilion 500 offers power and expandability. Key features. Windows 7 Professional 64-bit. 4th generation Intel Core i3-4130 processor. 4GB PC3-12800 DDR3-1600 SDRAM memory 1x4GB (expandable to 16GB). 1TB 7200RPM Serial ATA hard drive. Intel HD Graphics 4400. USB keyboard with volume control and optical mouse. Super Multi DVD Burner. 4 USB 3.0. Wireless LAN 802.11b/g/n featuring Single-band (2.4Ghz). 1 year limited hardware warranty and 1 year technical support. DTS Sound+: Delivers immersive surround sound complete with deep bass, clear dialog and maximum volume to multimedia content.. HP Simple Pass: Easily access your online accounts with a single password or PIN, and keep your identity to yourself. HP Simple Pass remembers your passwords, so you get to the good stuff faster.. Box: Finally, all of your mobile content is in one place. Free 25GB lifetime cloud storage from Box.. McAfee: Free 30-day Trial of McAfee Live Safe service included. McA fee Live Safe service enriches your digital life by protecting your data, identity and all your devices so you can connect with confidence. . 24x7 technical assistance
Product brand: HP
Target attributes: Operating System
Answer: attribute: operating system
value: windows 7
source: product title
attribute: operating system
value: windows 7
source: product description