Open Box: HP Laptop ProBook Intel Core i5 1st Gen 480M (2.66GHz) 4GB Memory 320GB HDD Intel HD Graphics 15.6" Windows 7 Professional 64-bit 4520s (XT990UT#ABA) - Newegg.com
parts-quick 2GB Memory for HP ProBook 4520s DDR3 PC3-10600 SODIMM RAM at Amazon.com
For HP ProBook 4520S 4720S Laptop Motherboard With HD4500 H6370M GPU 48.4GK06.011 H9265-4
Memory RAM Upgrade for HP ProBook 4520s 4GB DDR3 SODIMM | eBay
HP Probook 4520s upgrading CPU + RAM . Memory upgrade & upgrading processor with Intel i3 - YouTube
HP Probook 4520s 15.6" Laptop Windows 10 Home Intel i3 2.53GHz 4GB Ram 320GB Hard Drive DVD WiFi Power Adapter
HP ProBook 4520S Ram - How To Upgrading Memory Card DD3 (1333 MHz) - YouTube
HP Probook 4520s core i5 4gb Ram 320GB Hard drive 15.6 inch Screen Windows 10 Pro Laptop with HDMI output & charger in Excellent Working condition!!! for Sale in Aurora, IL - OfferUp