This can be a symptom of computers with Intel Smart Response Technology / Intel Rapid Storage Technology. Basically, Intel does fancy stuff (including the solid-state-drive cache) to make the disk drive faster and more reliable. It's related to RAID ... the same file may be stored in multiple places etc.
Intel has posted a PDF saying that DMRAID (the usual linux program to deal with RAID) is old and neglected, and incapable of understanding Intel's newest flavor of RAID. The other linux RAID program is mdadm (aka "MDRAID"), and supposedly works perfectly with ISRT / IRST and is supported by Intel.
Therefore, it seems to me that the most logical solution is the one suggested by oldfred here: Open ubuntu in liveCD or live-usb mode, open a terminal and type
sudo apt-get install mdadm
After that finishes (strangely, it might install an email service in the process), immediately run the livecd's installer. With any luck it will work perfectly.
When I encountered this same problem on my Dell Inspiron 14z, this procedure fixed the problem. [One other thing was, before I did the procedure above, I turned off acceleration in the Intel Rapid Storage Technology program within Windows 7.
I don't think that step was necessary though.]
grubonto the usb. It could also be looking in the USB /dev/sdb try selecting/dev/sdain the drop down menu. Does that show your existing partitions? – TrailRider Jul 30 '12 at 23:46sdbthat is a secondary or external drive, which is why I assumed that you were using a usb, there have been some problems with usb installs installing grub in the usb instead of the main(sda) drive. try checking the disk for errors, boot into the liveDVD and pressf6then select English as the lang. then in the menu that is showing select Check Disk for Errors it will take a few minutes. If it throws any errors then you will need to download and burn a new one. This looks like it could be a bad disk problem – TrailRider Jul 31 '12 at 0:06