OSx doesn't load from external HDD
 

I successfully installed 10.5.6 using iPC on my external hard drive but I cant seem to get it to load automatically.
I changed the boot order to usb hard drive as being first, but it still loads up windows 7, which is present on my laptop internal hard drive!

If i leave the iPC installation dvd, and if i boot it with
-v boot-uuid="MY EXTERNAL'S UUID HERE"

it loads into mac osx after 4-6 minutes!

Is there a way i could load into mac osx automatically? I dont want to go through the pain of typing my long UUID number everytime!!

And also, if anyone could help me regarding the problem of why I cannot format/erase/partition my internal hard drive. It gives me input/output error!
If this problem is fixed, I would certainly install it on my internal hard drive and osx should certainly boot up!

Please guys, Help me here!