I've seen this approach by Microsoft repair shops.When problems are
severe enough, they tend to back up your dataand then reformat the hard drive
(this is where Ubuntu likely was deleted)and then reinstall Windows 7, and then
restore your data.
Firstly: I'm a bit concerned that a repair shop would erase software from your
machine.Emphasize the last 2 words from my previous... "your machine"
I would hope at the very least they contacted you to advise that a hard
driveerasure was necessary.
Either way it looks like your 2nd Ubuntu install has some broken parts or
packages or the install did not run as expected. Here is what I suggest.
1. Make a CD or DVD copy of personal documents that you would not want to lose
--including any saved in Ubuntu if you can burn files to disc (this will take 2
steps, one for W7 and for Ubu).
2. Using the Ubuntu installer CD, start the machine using the CD. Once the
LIVE CD starts, look for the application "partition editor" or (by its formal
name) Gparted.
3. When Gparted starts, you will be presented with a "map" of the hard drive
and all of its partitions.
4. Take a screenshot of this partition map so you can post it here. Things like
"removing a linux installation" are easier to do when you can actually "see" how
the drive is divided up.The screenshot is important. But DON'T make any changes
yet with GParted. Windows installs tend to come with extra "RECOVERY"
partitions since MS and vendors no longer supply consumers with the Original
Operating System CDs
5. If possible, follow the help guides to make a "Product Recovery CD/DVD" for
Windows 7 because you never know...
In GParted, a Windows partition can be either FAT32 or NTFS. NTFS is usually
the file system type for the "C" drive in Windows, and the RECOVERY partition
can be either NTFS or FAT32. The Ubuntu install is probably of type ext3 or
ext4 and there is likely /swap partition there as well.
You could, alternately, open up a Terminal in Ubuntu and enter the commanddf
-hand then post the results here (it's the text version of what Gparted would
show graphically) in a way.
Good Luck, let us know more info so we can guide you further.