Question Why do I have DDR3 slots when the manufacturer states that it only comes with ddr2

[Phuqmegod]

A friend wanted me to see if I could get his computer running it's 2008 m2n68-la. After swapping out all necessary parts I concluded the motherboard was bad and I ordered one online off eBay. I realize this is a very ancient model. After receiving motherboard I installed it however could not get it to post. I used known good components. When I went to the manual online it insists that this board uses ddr2 ram however it has DDR3 slots installed on it. I'm not an expert at this by all means but I've been working on computers for 5 years now I'm never ran into anything like this. I suspect a corrupted bios it won't get an AV signal no matter what I do any configuration
Any advice or help would surely be appreciated

 

[Lafong]

The RAM slots on your board have the notch close to the middle.............is that correct?

Rather than offset and clearly not in the middle.

Specs I see online say should be DDR 2.

https://www.buildcomputers.net/ddr2-vs-ddr3.html

 

[SkyNetRising]

When I went to the manual online it insists that this board uses ddr2 ram however it has DDR3 slots installed on it. I'm not an expert at this by all means but I've been working on computers for 5 years now I'm never ran into anything like this. I suspect a corrupted bios it won't get an AV signal no matter what I do any configuration
Any advice or help would surely be appreciated

There are different variations of this board (different board revisions).
Some have DDR2, some have DDR3, but model name is the same.
Very confusing. Have to agree.

Anyway - you can't install DDR2 module into DDR3 slot. So only correct type ram modules can be used.

Pay attention, where middle notch is located: