Error while installing ubuntu 12.04

view story

http://askubuntu.com – I had ubuntu 11.04 installed on my laptop. Then I installed windows 7 and tried to install ubuntu 12.04 on other partition. but when I select try ubuntu without installing or install ubuntu I get same error, "Kernel panic - not syncing : VFS : Unable to mount root fs on unknows-block (0,0)" "Pid:1, comm: swapper/0 Not tainted 3.2.0-23-generic-pae #36 ubuntu" (HowTos)