I recently installed Ubuntu 12.04 alongside Windows 7. It was working fine, but now when I try to boot with Ubuntu after GRUB boot menu I get this.

Try (hd0,0): NTFS5: No wubildr

Try (hd0,1): Extended:

Try (hd0,2): Invalid or null

Try (hd0,3): Invalid or null

Try (hd0,4): NTFS5: No wubildr

Try (hd0,5): Extended:

Try (hd0,5): NTFS5: No wubildr

Try (hd0,6): Extended:

Try (hd0,6): FAT32: No WUBILDR

Try (fd0): Invalid or null

Error: Cannot find GRLDR in all devices. Press ctrl+alt+del to restart.

And when I press ctrl+alt+del it restarts the computer and if I chose to boot with Ubuntu the same thing happens again, but Windows works fine.