now unable to boot

[mosaic2s]

I had installed 12.04 as a fresh install on 60gb primary partition on a 320gb hdd. experimented with UNITY interface.
Then, on an impulse I installed xfce desktop over 12.04. Thereafter I saw 5 types of DE.

Gnome,
Gnome classic no effects,
xfce,
xfce standard,
unity 2D.


I logged into each one of them and finally settled for Gnome classic no effects. It was smooth but the system now refuses to boot into 60gb. It simply hangs while showing XUBUNTU blue landscape.

I am able to access the data while booting from the secondary partition into 10.04LTS.

How do I get back the control of 12.04? Can i delete some folders or modify settings from 10.04 LTS?

[mosaic2s]

finally moved the data to other partition and installed xubuntu 12.04 fresh.

however, i have moved back to 10.04 LTS since it offers stable interface unlike 12.04 that hangs or says internal error more than once a day.