Before you start -first- boot Windows and save the most precious files you have to a thumbdrive, or write them to a CD, or better yet, backup Windows completely. You know, however bug-free the procedure is, there is always a chance for human operating error, or simply someone tripping over the power cord at exactly the wrong moment. No procedure as involved as installing a new partition and OS can ever be 100% safe, but if you are careful it's unlikely to fail. Still, it's better to be safe than sorry, so backup those wedding pictures, etc.
After that, run Windows de-fragmentation utility, so that all the files on the drive are moved to the "start" of the disk-drive. In principle the partitioner will also do this, but lets make this as safe as possible, and make sure the partitioner has as little as possible to do, so it finishes it's "dangerous" job quickly.
First a warning. Use the gOS 1.0.1 version, you can also use the gOS 2.0.0-beta1 version, but it's not as complete as rev 1, and buggier, the following instruction assumes you are using gOS 1.
Boot the Live_CD, and if you like what you see run the installer. But if you have less that 256 MB or RAM in your machine, it might be wise to shut down one unneeded application, which might interfere when it auto-starts during the install. I am talking about the the update-notifier.
from the applications > Administration menu start the System monitor. on the tab-page Processes, find the process "update-notifier", and "end_process" it. On second thought, it's always better to do this, even with more than 256MB of RAM.
Now you can run the installer and follow the instructions, until the partitioning routine starts.
Now, this is the important part, if you get to the part where the disk partitioner is started, and it asks you how to use the hard-disk DO NOT CHOOSE THE "GUIDED - USE ENTIRE DISK" option, or windows WILL be wiped from the drive!
I repeat do NOT choose to use the entire hard-disk for gOS (the option "Guided - use entire disk")!
If a windows partition exists on your primary hard-disk gOS detects it and it -will- offer to share the hard disk with windows. the exact wording of this choice is:
"guided - re size", and some technical bla bla behind it which you can ignore. Check that this option is chosen (it should be per default).
Below it, you should see a drag-bar with "new partition size" in front of it. With the drag--bar you can determine how big the new partition will get, and how much will remain for Windows. Per default the installer will more or less split the disk in the middle, I suggest to leave it like that, because it's easy to misinterpret this option, and end up with a very small windows partition, instead of a very small gOS partition. You can change the partition sizes afterward with the live CD version of "Gparted", the Linux partitioner. read below.
(You will also get a third option "Manual", which is for experts who want to choose which partitions gOS should use manually. Leave it alone.)
Now start the installer partitioner, and WAIT. This is very important because you might lose the Windows partition. Partitioning a drive, (certainly if you did not de-fragment your windows system before) can be very time consuming, and uses all available CPU resources, so it can look like the computer has crashed, even the cursor might not move when you move the mouse, still wait! If you turn off your PC now, say can goodbye to your windows system (it might be rescued, but do not count on it), so leave the installer running! Just give it an hour or more [it took me 3]. But check regularly, as it could also take just 5 minutes. If the partitioner is ready, the rest of the installation will commence automatically, and it will install all the needed packages (software), just let it do this and do NOT abort this process, because in the very end the installer has to install the "grub" boot manager, to make a dual boot system out of your system, only after that is done and gOS gives the "all ready sign" you can reboot.
If anything goes wrong during the install, and you can't get windows to boot, don't panic! Chances are good you can restore the original boot sector for windows, so you can still boot windows. just don't go experimenting with it, but ask here first for instructions how to reset the boot sector. Or read this: []
You can always use Linux's regular partitioning program Gparted, (which is available on the gOS 1.0.1 live CD ), to change the partion sizes belonging to Windows/gOS. In theory the partioner is also available on the installer hard-disk version, but be aware NOT to change the partition where the version of Linux you are running the partitioner on, it's like sawing off the tree branch you are sitting on, not a good idea to do!.
Use the Live_CD if you want to change the Windows/gOS partition size!
slightly edited from mahjongg at []
Changing Default Boot Partition w/grub
You need to edit /boot/grub/menu.lst and change the default boot number. First back it up.
sudo cp /boot/grub/menu.lst /boot/grub/menu.lst.backup
gksudo gedit /boot/grub/menu.lst
Search for the line "default 0" and change the number to the count it takes to get to XP. At the bottom of menu.lst you will see you operating systems. Start at the top and at zero to get the correct number. Usually XP is the 4 entry, so the number will be 3.