I had some problems with my Windows and I formated the Windows partition. I have Linux in another partition, but now (after Windows partition format) I can't choose the boot, like before to format the Windows partition.
What can I do to have again the window screen to choose between the Windows boot and Linux boot?
Need more detail. The short answer is that you have to reinstall the boot-loader - Windows has overwritten it with its own one. You're most likely using either lilo or grub. If you use lilo, boot the recovery CD and then reinstall it by chrooting into the old disk and running lilo.