Chipset Heatsink not Detected | Intel Q45

[TweakyGhost]

My Dell Optiplex 755 is showing a blinking orange light with Diag code 3. As referred by diagnostic guide for optiplex, it is a processor problem. But can it be the motherboard? I have another Processor (Pentium D 945) But I don't think q45 supports it.
Update: Diag lights 123 and on screen message "Alert! Chipset heatsink not detected"

 

[Calvin7]

That is a 2007 model. I would replace the battery in it.
https://www.batterybob.com/products/252-maxell-cr2032-5-batteries/

 

[TweakyGhost]

I replaced the battery with a working one and it made it into bios. Now giving error "Alert! Chipset heat sink not detected.

 

[Calvin7]

How to restore the BIOS (System Setup) defaults on a Dell:
1. Power on the system.
2. While the blue Dell logo is visible, press the < F2 > key to enter the System Setup.
3. Press the < Num Lock > key, and verify that the Num Lock light is on.
4. Press the < Caps Lock > key, and verify that the Caps Lock light is on.
5. Press the < Scroll Lock > key, and verify that the Scroll Lock light is on. The lights on the keyboard should all be illuminated as in Figure 1.
6. Press the < Alt >+< F > keys at the same time. The system will beep as the setup defaults are restored.
7. Press the < Alt >+< B > keys at the same time to restart the system. The changes are automatically saved.

 

[TweakyGhost]

How to restore the BIOS (System Setup) defaults on a Dell:
1. Power on the system.
2. While the blue Dell logo is visible, press the < F2 > key to enter the System Setup.
3. Press the < Num Lock > key, and verify that the Num Lock light is on.
4. Press the < Caps Lock > key, and verify that the Caps Lock light is on.
5. Press the < Scroll Lock > key, and verify that the Scroll Lock light is on. The lights on the keyboard should all be illuminated as in Figure 1.
6. Press the < Alt >+< F > keys at the same time. The system will beep as the setup defaults are restored.
7. Press the < Alt >+< B > keys at the same time to restart the system. The changes are automatically saved.

Well, but I can't even go into setup cuz of the heatsink error...