Unable to dual boot after running Tweaking.com

[StripleR]

 
I have W7 and Ubuntu loaded on my Aspire 5742.
After finally working out that my BSOD was caused by faulty RAM, I re installed W7 but had problems getting Windows Update to install Service Pack 1.

Eventually I fixed Windows Update and ran Tweaking.com.
Now I am unable to boot Ubuntu- I press F12 on boot up but am only given W7 as my boot option.
I have checked with Disk Manager and the HDD is marked as Basic.

I tried using the Ubuntu CD to access the drive.  It tells me I have Ubuntu installed but only gives me an option to delete it and re install.

I have run out of ideas

Any suggestions are appreciated.

[Shane]

Odd. I dont have any commands that would change the boot setting in the system.

To dual boot ubuntu will change the boot sector to show the 2 options. If Windows replaced it and put its own back then you would only see the Windows option.

All that needs to be done is to have the boot sector put back. Which is the Ubuntu GRUB bootloader.

https://help.ubuntu.com/community/RestoreUbuntu/XP/Vista/7Bootloader

http://ubuntuforums.org/showthread.php?t=1825077

But I am curious to what repair would have had Windows do anything to the boot sector since I dont have anything that aims for the boot sector.

Shane