My motherboard DH61HO Beeps after several days ram error beep

I have issues with my board it beepes three times likely ram error but i clean my board so much after opening all components and after 1 days it beeps and after 2nd restart it starts.


THAT'S HOW IT HAPPENS.....

I have 4gb ddr3 ram firstly after that i install another stick 4 gb total 8gb ddr3 1333mhz.

It workes perfectly since 1 year

Then i also upgrade my board bios and after two days i also installed gtx 750ti

And after that all stuff updating bios and add gtx 750ti, my pc beeps after two days pc beeps three time and after 2nd,3rd restart it bootup's

As, the ram i added is very cheap cost me 11$ only kllisre 4gb ddr3 1333, is it possible that any problem with the new ram.

Please help me out of this, till now my pc is working after servel restarts but i feel its not good.

Please help????