Os booting problem

What do you mean by installing driver after format?
Format is a command that destroy all the data on your harddisk and creates new file system. This means that if you have formated your harddisk it is more or less probable that you don't have operating system anymore, so there is nothing to boot.
I need more information to help you.

you have a windows system file corruption on the c_437.nls file which is a national languages file required by windows to run.

repair this problem following these instructions-

1. Boot your computer from your Windows installation CD- ie-insert the CD and restart your computer.
2. Select 'R' for the recovery console and log on as administrator.
3. At the command prompt type the following:
cd system32
then press enter
4. Then type the following:
ren c_437.nls c_437.old
then press enter
4. Then type the following:
EXPAND D:\I386\c_437.nl_ C:\WINDOWS\system32\c_437.nls
then press enter

(If your CD drive is different than D: or your primary hard
drive/partition is other than C:, substitute the appropriate
drive letters.)
4. Select yes when you're prompted to overwrite the existing file.
5. Reboot the computer.

Depending on the level of file corruption, you may have to repeat this
process for additional files. To do this follow the instructions above substituting the file name.

//javaftper

Sounds like you have a corrupt ntldr.dll file. You will need to insert you windows disk and repair the dll file, here are links with detailed instructions,

This is for windows xp
http://pcsupport.about.com/od/operatingsystems/ss/instxprepair1.htm

This is for windows vista
http://pcsupport.about.com/od/toolsofthetrade/ss/windows-vista-startup-repair.htm

Format the drive.

This is because of either the system has shutdown while it was processing a windows file. sometimes repairing the OS or running a CHKDSK /R in the recovery console will fix this problem. if that doesnt help i recommend you change your HDD

probably not easiest way is get a cd and do a fresh install

You should put the drive back in the external caddy, delete the format, partition the drive for NTFS. format the drive and set as active.

Hi, I think that your os has been crashed. So insert your disk and boot your system and check that your BIOS will boot from CD (Boot preference - CD ROM). And install a fresh copy of your os. Let me know the result.

u need to boot from the cd rom & now u have format both of parttion c: & d then u can use on os

You can do format while rebooting your pc and opening it in safemode command prompt that arrives by pressing F5 or F8. First you format the drives in which your OS is not present. Then format your primary hard drive on which OS is installed. In command prompt write C:/>formact C:\