Did you check your boot.ini file for correct entries?
And please check this:
When I select Linux from the boot menu, I get a frozen "GRUB" (or an "L" in the case of LILO)
Make sure you created the linux.bin file correctly with the dd command. If you think you ran the command correctly, the problem may be that your /boot partition is beyond cylinder 1024 and your BIOS can't reach it. At system startup, the Windows boot loader lists the choices from boot.ini. When you select Linux, the boot loader then loads the 512-byte linux.bin file, and then BIOS tries to access the /boot partition to run GRUB. Some BIOS implementations can only address the first 1024 cylinders of a hard drive, which corresponds to ~8.5 GB. How do you fix this? Create your /boot partition before cylinder 1024; i.e. before ~8.5 GB.
http://www.geocities.com/epark/linux/grub-w2k-HOWTO.html