grub2 can not boot windows 7
 

menuentry "Windows 7 (loader) (on /dev/sda1)" {
insmod part_msdos
insmod ntfs
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 3850d16450d12980
chainloader +1
}

This is automaticly genarated after installed ubuntu 10.10. It shows black screen with a flashing cursor after press enter.
Grub 0.97 also does this with:
title win7
fallback 2
find --set-root --ignore-floppies /bootmgr
chainloader /bootmgr
savedefault --wait=2

But the wierd thing is my usb stick can boot windows 7 succesfully with the same configuration. Whats wrong with that? How can i do with grub.cfg?

It looks like you are trying to boot a recovery partition. From terminal run the command sudo fdisk -l and post back.

Another way is to boot your usb and look at the boot/grub/cfg for the windows entry and then change your installed (please read this first).