My CPU temperatures were getting high, so I removed the cooler, cleaned the CPU and cooler, applied new thermal paste, and reinstalled everything. Since then, the computer powers on but produces no display or POST. The RAM lighting no longer turns on either, even though it used to light up immediately. All case fans spin, but the GPU fans do not. The cables appear to be connected correctly. I've already reseated the RAM, CPU, and cooler, loosened the cooler screws, and removed the CMOS battery. I also had to remove the RAM temporarily to make room while working on the cooler, but I put it back afterward. What else should I check?
3 Answers
Start by checking the CPU and motherboard socket carefully. Look for bent or damaged pins, debris, or discoloration on the contacts. Also make sure the CPU power connector and the motherboard’s main power connector are fully seated. If you find bent pins, be extremely careful—straightening them can sometimes work, but it can also cause permanent damage.
A loose power connection is very possible, especially since the RAM lighting stopped at the same time. Turn the power supply off, unplug the system, and disconnect and reconnect every PSU cable at both ends if your power supply is modular. Pay particular attention to the 24-pin motherboard cable and the 8-pin CPU power cable. Also inspect the board for any accidental damage.
The GPU fans not spinning may be normal—many graphics cards keep their fans off when they’re cool. For troubleshooting, try the monitor cable from another port, confirm the monitor is on the correct input, and test with one RAM stick at a time in the recommended slot. Make sure the cooler isn’t tightened so aggressively that it puts pressure on the motherboard or socket.
I only removed the cooler, cleaned the CPU and cooler, applied the paste, and reinstalled everything. I didn’t notice anything unusual with the CPU or socket, but I’ll inspect them more closely.