How can I boot from the install CD?
Same way as when you installed your system. It may not be possible to boot into your system from the cd though. Try to see if it has some rescue function or if you get a list menu.
Once you get into the system do
dd if=/dev/hda2 of=/bootsect.lnx bs=512 count=1
if /dev/hda2 is where your linux system is. Otherwise you need to change it to where the system is installed. Unless you installed your system on reiserfs, most likely it is ext2 or ext3, you can access it from windows with the program explore2fs (google for it). Then you can just copy the file bootsect.lnx over to C:\bootsect.lnx. Then you need to edit boot.ini.
If you are new to linux I suggest you try a live cd. You just put it in your cd drive and start your computer and linux will load automatically, running only in your ram. It won't affect your harddrive at all. You can try Knoppix, Slax or Kanotix and many more. Knoppix is the most famous, but Slax is my personal favorite. It has the most useful programs and a nice desktop in less than 180 MB.
Goto distrowatch.com and check out which distros are most popular. They have links to all downloads.
Just found this:
which is a free software that should be able to do just what you want from windows.