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I downloaded Ubuntu 12.04 desktop edition. Used Universal USB installer to create a bootable USB. Restarted with the USB plugged in. Pressed F10 and selected Sony (my pendrive model). System restarted and is now stuck at a black screen with a cursor blinking.
Additional info: I created an iso file from Ubuntu 10.10 and burn it to the flash drive using Universal USB installer. System proceeded till the screen where it asks me to "Try Ubuntu". But when I click it, the pure black screen with Ubuntu written at the bottom that appears slowly fades to a different black with the name slowly fading out. And it does not proceed any further. (I went through some of the other posts and I understand that it may be a problem due to the "modeset", but please confirm)
EDIT : fixed the problem by selecting "help me boot from CD" option. It extracted the files from the pen drive and asked me to reboot. Worked perfectly. Thanks for all the help. Cheers.