Intel dp45sg memory problem?

Hi folks,

Having a very strange problem started since 2 days back, getting three beeps at POST. Removed and reseated ram (Kingston 2Gb DDR3 X 4), no help. Decided to try seating individually, discovered that if I populate DIMM 0, channel B ONLY, computer works normally but very slow. Any time there is a ram stick in DIMM 0, channel A (no matter what rest of configuration looks like) then I get the 3 beep code. DP45SG setup guide says, "Regardless of the memory configuration used (dual or single channel), Channel A, DIMM 0 must always be populated. This is a requirement of the ICH10R Manageability Engine feature." But populating DIMM 0, Channel A is exactly what yields the triple beeps, while populating only DIMM 0, Channel B shouldn't even work (but it does). So, is this a mobo problem? Am I missing something? I am not confusing Channel A & B. I know what I'm looking at and right now posting this as my RAMs are in channel B and no stick is present in the channel A button. Please help me out appreciate it

Thx for the reply yes i did try other ram modules, everything was working fine since the last 2 days, its more then 5 years i am using this PC with 8gigs of Ram all kingston but suddenly it gives error in the channel A of the motherboard as i mention in the post, i am using KVR1333D3N9/2G 1.5v, hope that helps
Also today i just take my all modules to make sure if they work or not and all of them work perfectly fine on other DDR3 mobo