First, I do not know what do you mean by SDK?????..Could you explain it?.
Second, DON'T EVER install grub in a PARTITION, IT will cause a lot of problems..You had to install to sda...That was a real bad thing to do.
You must read or ask before doing something you are not familiar with..
To recover Grub, you have 3 ways, but I'll give you the easiest one:
1. Need a liveCD, in your case use Ubuntu 11 or so using kernel 3.2 and according to the BT5 platform (if 32bits, use a Ubuntu 32 bits, if 64bits, use Ubuntu 64 bits), Do not use a 32bits in recovering a 64bit distro or the other way around, it will cause you many issues, bad issues.
2. Once the DVD burned, boot with it...
3. You must have identified the partition to recover, the one you installed BT5, I belive is sda5...
4. Once in Ubuntu, make sure about partition: open up a terminal and type: sudo fdisk -l and identify your BT5 partition, let's say is /dev/sda5 (hate the sudo, I'm debianist, sorry)
5. Create a mounting point for mounting BT5 partition, we can name it, let's say BT5, in the /temp directory, so we do: sudo mkdir /tmp/BT5
6. Mount BT5 partition (/dev/sda5): sudo mount -t ext4 /dev/sda5 /tmp/BT5 Now partition is mounted.
7. Now we re-insert/reinstall grub2: type this: sudo grub-install --root-directory=/tmp/BT5 /dev/sda (sda not sda1)
Once rebooted, you should see the Grub2 menu, including all Other OS (Windows7, etc)..If no other OS are listed, do not worry, login to BT5, and do this:
In case no OS are listed in grub menu:
1. Open up a terminal and type : os-prober The output will show the Win7 partition.
2. type this: update-grub, it will recreate and add all OS detected by os-prober.
Now you should see all OS...If still no Win7 shows up in grub menu, we have to insert it manually, but first try this...Then if no Win7 is shown in menu, I'll instruct you how to do it manually..It's easy too, but first try what I posted..
7. Now once partition mounted