Sorry about the excessively long question, but I figured giving more information would be better.

I recently bought a new desktop for myself, running Windows 7. It has two hard drives, and I wanted to install Ubuntu on a small partition on the second hard drive. I created 25GB "free space" in Windows and ran a LiveCD install. I wanted to select the install options myself but accidentally selected "Install alongside Windows 7," but it seemed to pick up the free space and installed itself there as I wanted it to. However, I was told that the bootloader installation had failed. I chose to "Cancel installation," leaving my computer unable to boot. I wiped my computer and reinstalled Windows.

After that, I tried installing Ubuntu through Windows using WUBI, once using files from my LiveCD and once downloading everything again. Both times the install succeeded, but both times when I restarted and tried to load Ubuntu, it gave me an error - wubildr.mbr was corrupt or missing. I checked in Windows - it was indeed present on the C:\ drive.

I went back to the LiveCD installation, this time going the custom options route. I assigned 16GB to an Ext4 journaling file system and 10GB to a swap file. I got the same bootloader error as before. Being prompted to select a different partition to install the bootloader to, I first tried the partition Ubuntu was installed on. A window came up saying that the install had succeeded, but a second window gave me the same error and choices as before. I went through every single option it gave me, including the Windows partition and the hard drives themselves (dev/sda, dev/sdb). Same result. I then chose to not install a bootloader. Windows still works fine, and I assume Ubuntu has installed but is unbootable.

Knowing that my computer could potentially brick itself again - and, this time around, with a lot of data to lose and hassle to go through if I mess it up - I really don't want to do anything without some advice. So I'll ask this:

a) Why did the bootloader fail to install? Can I fix the error and install Ubuntu fresh?

b) Is there any way to get around the error, install the bootloader, and point it towards an existing installation of Ubuntu?

c) Is there a quicker and easier solution I might have missed?

EDIT: Thanks for the tip, AthloX. After testing the liveCD in Virtualbox with no installation problems, I looked around for some alternate bootloaders but had no success.

I attempted another install, which installed the bootloader and Ubuntu just fine but bricked Windows 7. I wiped both hard disks clean, including some "System Reserved" partitions I hadn't noticed before, before re-installing Windows 7 on one hard drive and immediately afterwards installing Ubuntu on the other.

Now the computer boots into Windows, but I can pop into the BIOS at startup to boot into Ubunbtu via it's bootloader, and I'm guessing it'll only take a bit of poking at the BIOS to swap the load order. Many thanks!