Internet, Networking, & Security Home Networking How to Check for Disconnected Computer Power Cable Connections by Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated on May 17, 2019 Home Networking The Wireless Connection Routers & Firewalls Network Hubs ISP Broadband Ethernet Installing & Upgrading Wi-Fi & Wireless Tweet Share Email If your computer won't turn on, the problem could be as simple as loose power cables. If the power cables aren't connected properly, your computer might also shut off abruptly, so you might look for loose power connections even if your computer starts but then shuts off. Checking your PC for loose power cables is easy, and the idea is simple: locate every point the cables connect, and then confirm that they're firmly in place. 01 of 03 Check the Power Cable Behind the Computer Case Power Cable Connection Behind Computer Case. © Tim Fisher Power cables often wiggle loose from PC cases over time or sometimes after being moved around. Checking every point where electricity is delivered to the computer system is usually a first step when a computer isn't receiving power. The first place to start is with the power cable that connects at the rear of the computer case. The power cable should fit firmly in the three-pronged port on the power supply. 02 of 03 Verify PC Power Cable Is Securely Plugged In Power Cable Connections on Power Strip. © Tim Fisher Follow the power cable from the back of the computer case to the wall outlet, surge protector, or power strip that it is (or should be) plugged in to. If your PC is attached to a battery backup unit, follow the cable there. Make sure the power cable is securely plugged in. 03 of 03 Verify Power Strip Or Surge Protector Is Securely Plugged In a Wall Outlet Power Cable Connection on Wall Outlet. © Tim Fisher If the power cable from the PC case was plugged into the wall outlet in the last step, your verification is already complete. If your power cable is plugged into a surge protector or a power strip, ensure that it's securely plugged into the wall outlet. The same is true for battery backup: make sure the backup unit is firmly plugged in to its power source (likely the wall).