No Root File Systems is defined

The Wubi install is a bit wobbly as it combines the worst aspects of both OS's. A better way to install Ubuntu to combine the best of both making a thoroughly enjoyable and robust, flexible system is to follow these instructions
https://help.ubuntu.com/community/WindowsDualBoot

A little bit more work but thoroughly worthwhile. It should help you deal with the Wubi afterwards too
https://wiki.ubuntu.com/WubiGuide#How%20do%20I%20migrate%20to%20a%20real%20partition,%20and/or%20get%20rid%20of%20Windows%20entirely

Good luck and regards from
Tom :)

Hi Tom,
According to your advice I tried to install Ubuntu on a separate partition. As I didn't have extra partition, I thought I'll re size the existing windows partition. After defragmenting widows partition I started my laptop through Ubuntu live cd.
Firstly, I didn't get automatic partitioning option, also Ubuntu is not showing any of partitions present on my hard disk when I open partition manager application(Gparted), however I can access all partitions and data by going to menu places>computer...
I guess this is the reason why I'm getting the error "No Root File Systems is defined". Ubuntu is not displaying/recognizing any partitions for resizing rather than It is showing entire hard disk as no partitions existing.....

Any idea about this....?

regards,
Pranav

Dohh, sorry about this. The partitioning section is quite a long way through the installing process. The error "No Root File Systems is defined" is due to a tiny un-obvious feature. One of the partitions, the one you want Ubuntu to be installed to must have it's "Mount Point" set to "/", the / is the root of the file-structure. Folders such as /home/pranav/documents build off the /

Good luck on your 3rd attempt
Regards from
Tom :)

When you do eventually get a fair way into the installing process you shoudl get to the Partitioning section. I definitely think that it's best to choose "Manual" rather than "Guided" at this point.

If you are still having trouble with this then please post it as a new question. Only the most recent questions tend to get looked at so posting/reposting a question just before america arrives online after work/school gives the best chance of getting a good few answers.
https://answers.launchpad.net/ubuntu/+addquestion

If the problem has been resolved then please follow the link to the forum thread and mark it as Solved.

Good luck and many regards from
Tom :)

Hi Tom,

I have dropped that idea for a while.... I'll again find the solution some other time...
Thanks for your support..

Regards,
Pranav

Thanks for your kind message. It was a good struggle for a while there. I just wish i could attach screenshots - then it'd be much easier

Good luck and thank again, regards from
Tom :)