To go completely safe you can install
GRUB on a
USB stick (you have that option in the installation menu, drop-down list at the bottom). I have such set-up and have been using it for a long time now. It serves me quite well as it leaves Windows to it's own devices.
I, for example, clone Windows system partitions with Clonezilla to have a snap-shot of the system and "reinstall Windows" as needed in 5 minutes. GRUB stays untouched on my USB then, no need to reinstall it. Works like a charm!
I'm using Windows Vista though.
Edit: HOW-TO install GRUB to USB stick
You can install GRUB to USB stick by going with "Something else" option in the installation process, that means a bit more advanced work. You should try it out though.
Please proceed with care and do not do any changes to your disk if you are unsure what you are doing. Ask more questions if needed, but do take a look at this approach.
First, you need to allocate space for your Ubuntu. That means creating free space on your hard drive. Either achieve that through your system's disk management or boot Ubuntu from LiveCD and start GParted. Then do:
Insert your USB stick.
shrink one of your partitions
- things to consider: how many partitions have you got (you can have maximum 4 Primary partitions) that is why you'll be creating
- what are their sizes and how much space do you consider enough for Ubuntu (in most cases for system alone and some space 10GB is more than enough)
Extended Partition from that (select and create a new partition in the
unallocated space and allocate 100%)
In that extended partition you will make Logical Disks:
system partition - bare minimum (a root main system folder, the
/, best go with
ext4 format) and
swap partition (format to
- you might consider making a separate
/home partition - this way your personal files and settings will be safe in case you need to re-install Ubuntu. I recommend it.
If you are only making
system partition and
swap, allocate as much space for swap as you have memory and as much space for system partition as you can spare.
If you go with separate
/home partition, 10GB should be enough for
system partition, as much as memory for
swap and the rest for your files like music, videos, pictures and settings and more.
Done? Good, close GParted.
Once your partitions are ready, click on
Install Ubuntu (it will probably ask you to unmount device /dev/sdb1 or some such) answer yes.
When at the method prompt - choose
Something else option. You will notice at the bottom of the window
Device for boot loader installation. We will come back to that.
For each partition you have created in previous step - select it and click
Change. The options I spoke earlier about:
/home they are called
Mount Points and this is what you must choose for each. For
swap, click it and use as
Installing GRUB - from the drop-down menu choose your device (if only one usb device is present, it will be
Make sure you have chosen /dev/sdb and not /dev/sdb(n), where n is a number. It must be /dev/sdb or whatever letter your USB stick was assigned.
Review your choices, make sure everything is OK. Double-make sure. Click install now. Voila!
Hope it helps.