If the 7N400 Pro 2 is laid out the same as my 7N400 Pro 1, then there is a switch on the board for setting FSB frequencies to either "Auto" - set in BIOS, or "200MHz" - ie, Athlon and Duron @ 200MHz DDR FSB. Switch this to "on".
The comp is detecting ur cpu as 15*100=1500MHz, not 15*133=2000MHz.
This should work fine. At least, it did for me.
Oh, and if u don't mind a tip, if ur looking for a Clr_CMOS jumper, there isn't one, i think. U have to remove the battery.
Athlon XP 2400+ @ 2160 180 FSB
GF4 Ti4200 @ 275/575
1GiG Kingston PC3200 @ 432MHz (Dual Channel)