Triple boot, a diifferent approach - why didn't it work ?

I have a system with three hard drives, one partitioned into two parts and two empty. I already had XP and Vista
installed on the two partitions of the first drive and wanted to add Ubuntu to one of the others. To prevent
damaging the Windows installations, I unplugged the Windows drive and installed Ubuntu. It booted OK. I then
plugged the Windows drive in and both versions worked OK. Using EasyBCD I then tried to add Ubuntu to the start
menu. I have tried many combinations of drive number and partition: 2/1; 2/2; 2/3; 2/4; 1/1; 1/2; 0/1; 0/2; to
locate the Ubuntu Grub boot file to no avail. Sometimes I get an error report that the file cannot be found,
sometimes the computer locks solid with a black screen. One point: when I add Ubuntu to the boot menu it always
lists the `drive' as C:, my XP drive. Is this correct or can it be edited ? In desperation I am even thinking of putting a switch on the Windows drive so I can easily disable it when using Ubuntu ! There must be a more elegant solution - any ideas ?
Yes I did, but for some reason I can't find the boot loader. Maybe it's the way I installed Ubuntu. I'm very frightened of messing up Vista and XP ( both legal and activated already) using the method mentioned as I'm not sure how to make sure Ubuntu and loader go in right place. I have absolutely no experience with Linux or it's loaders. Is there any way out of the mess I seem to have got myself into ?
Well spock, the best thing for you would be to boot from the Ubuntu CD or a Live CD and install grub to the bootsector of your Linux partition according to "Reinstalling GRUB" on

At any rate, there is almost no risk involved. It won't deactivate XP or Vista, and any mistakes can be fixed by doing a startup repair from the Vista DVD in under 5 minutes.

Good luck.