Can't boot into Windows after Installing Ubuntu on USB?

view full story

http://askubuntu.com – I'm new to Ubuntu. I've installed Ubuntu 12.04 on a USB flash drive. It boots fine from the USB stick. But if I remove it and boot again, Window 7 should boot. Well it doesn't. Seems like the hard disk is not there any more. Must have done something wrong while installing Ubuntu. My laptop is an Acer Aspire 1410 without a DVD reader. The USB flash drive is a 64G Sandisk Cruzer. I've check in the Bios and it still see the hard drive. When I'm on Ubuntu I'm also unable to see my local hard disk. How can I solve this problem? (HowTos)