Laptop begins boot but shows 90D Overheat message and shuts down

[Adacomp]

Every time this laptop is powered on it displays the 90D Overheat message. After hitting Enter it runs for about 5 secs and shuts down. I cleaned the heat sink vents and replaced the fan. I disconnected the battery and power adapter and held the power button for 30 secs and it still will not boot. I then reapplied thermal paste to the CPU. After reapplying thermal paste yesterday  it booted and ran fine. I tested it this morning and it's back to the initial problem of the 90D error and not booting. Some solutions say to update the BIOS but the computer will not run long enough to do that. I suspect a problem with the motherboard but wanted to run this by the community first. 

[Riddle_Decipher]

@Adacomp You've rightly diagnosed this to be a hardware malfunction and replacing the heat sink for that 90D error code, should resolve the issue,
The heat sink itself may look good but the tubes that move the heat from the processor to the fans may not be working properly.

you may order the replacement parts on the HP Parts Store, If you've already looked for it and couldn't find it on the HP Parts Store, you may want to get it locally at the online store such as Amazon or eBay, etc...as the part numbers are universal and let me know if the device is covered by the warranty, as it can be repaired free of charge if it is.

P.S: Welcome to HP Community 😉

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