my problem with my KK266

Last week, i built a new system with KK266 and some old parts inluding a 128m pc100 memory I was using before. i tried to change the DRAM CAS setting from 3 to 2 and the result was the system hanged: no beeping, the monitor in low power mode, but HD and CDrom still spinning from the sound they made. Then I tried to clear the CMOS by switching the jumper, but nothing came back better. Have I already got my memory finished? or some other reasons? thank you very much for any comments.