how to restore windows bootloader that doesn't let windows boot after ubuntu 11.04 installation?

Question

I installed Ubuntu 10.10 and chose the option of installation "alongside windows". Then I chose a drive where Windows 7, 64 bit was already installed. This drive had a capacity of 150GB. Ubuntu divided it into 100+50. I went along with that and installed Ubuntu 10.10 successfully. While booting windows 7 loader shows in the boot screen, but it does not boot after selecting the option and pressing enter. No error message is given, the screen just gets black and goes back to the operating system choice menu. Now i upgraded Ubuntu to 11.04.

I have Windows 7, 64 bit and Wiindows 7, 32 bit in two separate drives of mine. Windows 7, 64 bit is on the primary partition, while the 32 bit version is installed on an extended partition. I want to keep all the three operating systems. Please suggest me the best way to keep tem. I have already tried Windows 7's start up repair. But no gain. I also rebuild boot using testdisk.

Answer 1

Try this-

Follow the solution here. Once you get that working, you can boot into a ubuntu livecd and reinstall grub.

Answer 2

May guess is, that you corrupted Windows' bootloader. When you told Ubuntu to use the 150GB partition in chunks of 100GB and 50GB it might be that the disk was formated.