Boot to the XP CD.
Let it load up and then press F8 to agree to the licence agreement. You want to install a fresh copy of windows so press enter at the next screen. You will then come to this screen
Your partition should be highlighted. Press D to delete it. Windows will complain and ask if you really want to do it and you will have to press L to delete it. You should now just have raw space on your hard drive. Press C to create a new partition in the raw space.
Windows will assume that you just want to make one big partition but you don't want to do that. So type in the space you want for your XP partition. I suggest splitting the drive in half and devoting ten gigs to each partition. Type in 10240 for your XP partition. If you don't want to split it in half just type in how many MBs you want for your XP partition ( if you type in a number windows will "round" this number to make it make sense to itself, so don't worry it's normal).
Now you should have your main partition setup so press enter to install windows on it. Choose the NTFS file system. Don't use the quick method.
The first thing you want to do after installing windows is make sure that all of your drivers loaded. Click Start then Run and type in:
devmgmt.msc and press enter. This will take you to device manger. If you see any yellow question marks or exclamation points you will need a driver for that device.
Now that you have XP installed and all of your drivers loaded it's time to set up that new partition. Click Start then Run and type in
diskmgmt.msc and press enter. This will take you to disk management. You can also get there by clicking Start and then right click on My Computer and select Manage and then choose disk management.
In disk management you will see the raw space on your hard drive that we left alone earlier. It will be listed as unallocated and the disk icon will be listed as unknown. Right click the the disk icon and choose initialize. Now right click the unallocated pat of the drive and select New Partition. This will start the New Partition Wizard.
The New Partition Wizard will ask if you want to make a primary or an extended partition. Choose Primary. Then you will see a screen asking you for the size of the partition. If you just want those two partitions, pick the entire free space. Then you will be asked to assign your partition a drive letter. You can pick any letter you like other than C.
The last screen of the New Partition Wizard asks for the type of partition that you want to use. Again, you want to use the NTFS format and do not use the quick method. At this screen you can also assign the new drive a volume label. You can name it whatever you wish. something like "backup drive" would work. There should be no reason to change the Allocation unit size so just leave that alone. You can also enable file and folder compression if you wish. If you want to use compression you will be able to right click any folder or file in your new drive/partition and compress it. Compression is good for freeing up disk space on a drive that's filling up, but it slows down disk access, so use it only if you need to.
After this you will be back at the disk management screen and you should now see your new partition. To access it and start using it Click start then choose my computer and click on your new drive.
Congratulations you did it!
If you need any more help just post back
Good Luck!
