I found that not only the network doesn't work, but the filesystem has problems. The new kernel cannot see files created by the old one, and when I mount the fat32 partition, the system said the kernel didn't surport vfat.
Is it the module problem either?
I successfully installed Module-init-tools 0.9.14 and recompiled the kernel 2.6.0. Unfortunately, the system cannot boot now -- kernel panic :no init found,try passing init=option to kernel.
I used the install CDROM to boot and found that there was no hda in /dev, and chroot was not able to be found.