I tried cleaning the partition which had Ubuntu installed (but was corrupted somehow and I wanted to reinstall) - I used gparted for it. After deleting the partitions which contained ubuntu (I had another partition for windows), I tried re-installing ubuntu 12 - however, the installation failed complaining that there was no /dev/sda. When I tried gparted again via live CD, its unable to find any devices on the computer. I will run disk utility to gather more information - any other thoughts that could possibly help me get to the point where I can re-install ubuntu on my computer. I noticed the option for reformatting on disk utility but I have not tried it yet.

Edit: I am assuming that I may have corrupted/deleted the NTFS partition somehow since I am unable to see any deviced on gparted now. I am not entirely sure whether I should try format volume or drive via dis utility. I will try running a bad blocks check as well.

thanks in advance

Update:
I can neither format drive nor volume using disk utility - it complains about "Daemon is inhibited".

Update:

When I tried running benchmark drive performance, I received the following error:

Error benchmarking: helper exited with exit code 1: Error reading 104857600 bytes at 104857600 from /dev/sda when guesstimating buffer size: Input/output error

Update:
GParted was already running and possibly holding onto a lock. When I closed it, I was able to format the volume.

Update:
After formatting, I had issues with the ext4 filesystem. I tried formatting it again - got the error (approximate) below - any thoughts?

mke2fs:
could not erase sector2 - short read
could not erase block 0 - short read
could not erase sector 0 - short read