Sometimes you can not boot in your PC after making a partiton . And you get stuck in a black window at the boot time .This happens because after making the partition in your Hard disk the location of grub from which the OS loads may change .
To solve this problem and to boot into your OS follow the next steps :
Step 1 . Press “e” (edit) at the start up screen when OS loads .
Step 2. In the edit window watch the grub . Let , the grub says : root(hd0,9)
Edit this number and Try with some other combination like : root(hd0,10) and try to load from this modification .
Trial and error to get the real grub location from where you can boot .
Remember this real number .
Step 3. Boot from an Ubuntu live cd
Step 4. Open up a terminal and write : $ cd /boot/grub
Step 5. You have to edit the grub.cfg File of this folder.So, give the grub.cfg File write permission by : $ sudo chmod 777 grub.cfg
It will ask for your password . Give the password of your User if any.
( For the previous Ubuntu versions the grub file’s name is “menu.lst” , so in that case write : $ sudo chmod 777 menu.lst )
Step 6. Now open the grub.cfg file with an editor . Write on the terminal : $ gedit grub.cfg
( For previous versions write $ gedit menu.lst)
Step 7. Find the lines matched with your previous grub location (Let it was at root(hd0,9) or something like this ) and edit these lines with your real grub location . Say you found your real grub at root(hd0,10) . So replace root(hd0,9) with root(hd0,10)
Step 8. Save the file and restart your PC .
Wish this time you can boot to your OS properly . :)