Memory not allowing me to boot pc

[qqlessplz]

I have been running my matching for almost a year with 8 gigs of ram 2x4gb sticks in slots b1 and b2. when i put anything into a1 or a2 it doesnt post. tried the new ram 2x4g sticks in b1 and 2 and it works fine so ram isnt fault. CPU pins are not bent.

even if i put 1 stick into a1 or a2 - nothing posts?
MOBO is asus P8H77-v ram are all corsair 1333 DDR3.
700w corsair psu
128g ssd
1tb WD red

bios is updated i jsut wanted to increase ram and totally forgot about it not posting when i used those slots when i bought it a year ago.
So i have been using it for a year with 1 stick in black (B2 slot) and 1 stick in (B1 slot) Blue.
please can anyone help me?

 

[Entomber]

Are the new RAM sticks that you're trying to add identical to the ones you already have? If not, then your computer will not accept them.

When using multiple sticks of RAM, they must be identical in both frequency and CAS latency, otherwise many issues may arise, the least of which may be that your computer won't POST.

 

[Tradesman1]

If you had the problem before, you probably have a bad channel on the mobo or a faulty MC in the CP, another possible is that the CPU cooler is too tight in a corner or on one side throwing the CPU out of level and not having full contact with the pins, this is a typical reason for a channel to not work, could try loosening the cooler then snug it back down - not overly tight, and then try a stick in A1 and another in B1