You change the memory frequency in the BIOS. Go to "Genie Bios Settings"... you can change FSB in there, and you can go to "DRAM settings" to change the divider to what you want.
The best way to initially test your ram is to run it 1:1 with your FSB, so that you know exactly what mhz it's running at. To set 1:1 go to "DRAM Settings" in the "Genie BIOS Settings" section and set it to DDR400 (that's the 1:1 ratio).
To answer your 2nd question, test#5 is referring to memtest. You can enable the motherboard to run memtest in the "Genie Bios Settings" all the way to the bottom, I believe. Hit F10 and restart after you "Enable" memtest and you'll see it go to it. You can easily disable memtest going back into the bios and changing the setting for memtest to "Disable".
Good luck.