Please help me figure out these mounting points

Loatty

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Sep 22, 2015
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I've decided to pull apart my old pc, taking out the motherboard and tossing it out, along with the CPU, because those two died on me a few months ago... but now I want to replace them on the cheap (gonna use this system to mess around with Ubuntu, nothing else)... but I noticed the case doesn't have any stand-offs for the motherboard, just the sort of 'bumps', as seen in the picture below.... I checked, the previous motherboard didn't use anything to seperate the mounting crews from the 'bumps'.... can I just use those 'bumps' to safely mount a new motherboard, or should I buy a few rubber washers to put between the motherboard and the 'bumps'?

Picture (sorry for the big size, my bad)