I have same issues with same mobo and mem.
I have got into the bios by just inserting 1 stick of memory into slot 4, furthest black slot from cpu.
It is then a case of restarting until monitor is powered up then getting into bios and dropping memory to 533hz speed.
You should then be able to use the 2 sticks of mem.
IT IS A PAIN TO GET INTO THE BIOS and requires a lot of patience.