Need to change boot from Ubuntu to Win 7

I have a dual Ubuntu 11.10 and Windows 7 Home Basic booting system on my laptop (VAIO, specs at the end). Each time I switch on my laptop, Ubuntu's GRUB first shows me the options as to which OS to boot from. The choices include Ubuntu and Windows 7. To install Ubuntu, I made a 25 GB unallocated volume on my hard disk. Recently, while updating Ubuntu to its latest version, my internet crashed and the download only partly succeeded. After that, I have never been able to use Ubuntu on my laptop. However, GRUB is still functioning; each time I switch on, I still see the options as to which OS to boot from. If I choose Win7, then I get the usual Windows 7 Booting screen.
Basically, I now have 25GB of space lying unusable on my machine. I want to merge this with one of my other partitions. However, I fear that doing so would delete GRUB and make my laptop impossible to boot.
What steps should I take? Is there any way whereby I can safely delete Ubuntu and change the boot sequence from GRUB to the Windows boot program? (I guess it is BOOTMGR.EXE)

piezoelectron said:

I have a dual Ubuntu 11.10 and Windows 7 Home Basic booting system on my laptop (VAIO, specs at the end). Each time I switch on my laptop, Ubuntu's GRUB first shows me the options as to which OS to boot from. The choices include Ubuntu and Windows 7. To install Ubuntu, I made a 25 GB unallocated volume on my hard disk. Recently, while updating Ubuntu to its latest version, my internet crashed and the download only partly succeeded. After that, I have never been able to use Ubuntu on my laptop. However, GRUB is still functioning; each time I switch on, I still see the options as to which OS to boot from. If I choose Win7, then I get the usual Windows 7 Booting screen.
Basically, I now have 25GB of space lying unusable on my machine. I want to merge this with one of my other partitions. However, I fear that doing so would delete GRUB and make my laptop impossible to boot.
What steps should I take? Is there any way whereby I can safely delete Ubuntu and change the boot sequence from GRUB to the Windows boot program? (I guess it is BOOTMGR.EXE)

In Windows, download and install (free) EasyBCD. Click on BCD Deployment, then Write MBR. Done!

Or you can boot a Windows Recovery Disk if you have one, and use the repair facility.

EasyBCD is the easiest way to go, I think.