Here is the answer and works without any problems.
(I have Kali linux 32 bit dualboot with windows 7 ultimate 32 bit.)

Here is the tutorial how you can remove Kali linux and grub.

It’s not uninstall actually, just simply delete it.

Remove Kali linux installation.
Reinstall Kali linux with new disk space allocation.
Remove grub.

To remove Kali linux, which is dual booted with windows 7, you have to make sure that your windows 7 can still work well.

A. Fixing windows 7 boot manager

1. Prepare your win7 installation disk (dvd/usb), plug it in.
2. Start your computer, set the boot priority from bios setting (first boot usb, or cd/dvd room)
3. When windows 7 installation comes up, choose repair
4. Choose repair this computer with recovery tool, click next
5. Choose command prompt
6. Enter this command:

BootRec.exe /fixmbr

7. Reboot your computer

B. Remove kali linux

1. Now your computer should start the win 7 automatically.
2. Go to control panel > System and Security > Administrative Tools > Computer Management > choose Disk Management (under storage properties)
3. You will see clearly your computer partitions, delete your kali linux partition by right click > delete Volume
4. After it is deleted you will have new disk space and you can expand your other windows partition.

C. Remove Grub

Just delete grub partition by right click > delete Volume
After it is deleted you will have new disk space and you can expand your other windows partition.