I'll make this quick: I have an HP laptop with win7, I installed Ubuntu on a separate partition, and when I tried to boot win7 from grub I got the loading screen and no progress-ever. I did a /fixmbr with the windows recovery cd and got back windows, but wiped out grub and my access to Ubuntu. I reinstalled grub from the Ubuntu live usb ( I know I did this correctly) and now windows won't boot, again.

I'm a linux noob at a loss. Your wisdom is greatly appreciated!

Update in response to Scott Severance:

your instructions say to determine the main partition on my computer. I'm not sure what this means... my windows partition is at sda2, my boot partition is at sda1, and my linux root partition is at sda7... Which is the "main" partition?

UPDATE: I determined that you were probably referring to the linux root(/) partition, because this was the only partition for which I could follow your instructions without errors. Now, Windows is booting fine (thanks to /fixmbr), but even after the grub instructions there is no grub. It boots straight into windows.