There is one other way to boot linux, without altering your MBR. Install LILO on the superblock of your Linux partition, and aquire the 512 bytes of the superblock , like so..
dd if=/dev/hda of=/tmp/bootsect.lnx bs=1 count=512
I am assuming of course since hdb is windows, then hda must be where linux is, and this command is just an example, on the last part, of=/tmp/bootsect.lnx bs=1 count=512 , you can have the output somewhere else, just make sure you can make a copy of it, to a diskette, or somewhere where windows can see it, such as a FAT32 partition
Next, under windows, copy it to the root directory of your C:\ drive , and then edit boot.ini and add the following
you should also add timeout=30 (30secs) , or how many seconds you want, if that is not present in boot.ini.
Once you reboot you should have a prompt, with the choices of windows or linux. Now, keep in mind that you are using the NTLDR to call upon LILO with the bootsect.lnx file you have just created, this is how I boot, and it works just fine, since I can't install LILO to the MBR either.