It'll be #1, but you should be able to boot off the Ubuntu install DVD and then use that to reinstall GRUB. I wouldn't anticipate any problems with GRUB booting Win7, since it can boot Vista and 7 is really a minor update to Vista, but it couldn't hurt to look around a bit beforehand to find out for sure.
I currently have 3 partitions in use. One with Vista installed, One with Ubuntu installed, And the other with just a few files. The Bootloader I am using is GRUB, It replaced the Vista bootloader when I installed Ubuntu. Soon, I will be upgrading to Windows 7. Before I do, I would like to know what will happen to my bootloaders when I do.
I expect one of the following:
1. The Windows 7 Bootloader will overwrite GRUB and I will not be able to access Ubuntu OS.
2. The GRUB bootloader will remain and I will not be able to access Windows 7
3. The GRUB Bootloader will remain and I will be able to access both OS.
4. The whole thing will stuff up and I won't be able to access either OS.
Which one of these is most likely, and what should I do to make sure everything runs smoothly? I don't mind If I loose the Ubuntu Install, It's an old build now anyway.