The system cannot start after the kernel is compiled.

After the kernel is compiled, the system cannot start-Linux general technology-Linux programming and kernel information. The following is a detailed description. Thank you for your urgent help. My desktop OS is FC10 and the kernel version is 2.6.27.5. Because we need to compile the EV-uu module, and the kernel network code under 2.6.27.5 is different from the previous kernel version, we used 2.6.21.1 to compile the module and kernel.
Make dep
Make clean
Make modules
Make modules_install
Make bzImage
Make install
These are all done, and 2.6.21.1 is added to the menu in grub. I restarted my computer and selected 2.6.21.1 in the boot screen, but the following error occurs:
Reading all physical voumes. This may take a while...
Volume group "VolGroup00" not found
Mount: error mounting/dev/root on/sysroot as ext3: No such file or directory
Inout: ImPS/2 Generic Wheel Mouse as/class/input/input4
The system will not move here. I am not familiar with the system startup process. please help me see what is going on and how to solve it? Thank you!