My question is an extension of the previous one but because this is a totally new issue thus a new question...
So I can't install Ubuntu in my external drive I therefore removed my internal laptop hardisk (contain windows) & placed the external hardisk (previously in a Samsung USB 2.5' External Closure) of 160gb there...I ran installation using this profile
all as ext4.. swap 2000mb logical / 17000mb logical /home 9000mb logical /opt 14000mb logical rest free space...
Installation ran perfectly without the error mentioned in previous question. Now I tried luck by pulling out this internal hard (containing perfectly running copy of Ubuntu 12.10) & inserting it in Samsung enclosure to be used as USB...
I booted from this USB & walla Ubuntu did boot but wait it threw two nasty errors for being unable to mount /home & then /opt press S to skip & M manual recovery I chose to skip & I can login as a guest & can use Ubuntu?
From this experiment I concluded that Ubuntu doesnt support multiple partitions (/home & /opt) in a USB Hardisk, am I correct?
I reinstalled Ubuntu again making this hardisk as internal but this time with this profile (note only one / partition)
all as ext4.. swap 2000mb logical / 50000mb logical rest free space
I again made this act as external USB hardisk & Ubuntu finally ran successfully but flexibility of separate /home & /opt partitions was out of equation :(
I played a little bit with Ubuntu... then it was time to finally insert my Win7 (original) internal hardisk. After I booted to Windows, attached the external hard (containing Ubuntu) I formatted the free space left in Ubuntu installation as NTFS (because NTFS option wasn't available in gpart, another disappointment of having FAT32 but not NTFS). Now again I booted via this USB hardisk but it throwed me an error:
unknown filesystem grub rescue
& I was utterly dismayed & retired ungracefully :(