I'm assuming your laptop has only one drive, and not a dual-drive setup (such as HDD+SSD), and that one drive only has one partition. Note that if you have multiple partitions on the drive, this may fail.
Also, some of the block bits on the partition can be placed anywhere inside the data drive. This means that there is a limit to how much you can 'shrink' your Windows 7 installation and install Loki alongside.
Follow these steps.
- Boot up your Windows 7 installation.
- From the Start menu, type Disk Management.
- In disk management, select the Windows 7 partition. This will usually be the biggest partition residing on the drive.
- Right click the partition and select Shrink Partition.
- DM will automatically calculate how much storage space can be spared for the Loki installation. I recommend a base minimum of 10GB, although it can be much more less. (I think the very minimum is 7GB, but that only leaves a few GB for you to store your files.)
- Shrink the drive. DON'T SET UP PARTITIONS FOR LOKI JUST YET! We're going to do that directly in the installer.
- After you're done, boot up to the USB, select Something else, and continue.
- Let's say the amount you can use is in total, 20GB. Now you need to know how much RAM you have, and in this case we're going to assume 8GB. Halve that, and you get 4GB. Now, you need to subtract this from the total.
So 20GB - 4GB = 16GB.
- Make a drive in 16GB and set it as root(/) of the install. This is where all your OS files and your files would go.
- Last step! With the last 4GB, make a swap space, in case you use more than your RAM.
- You're done! Go ahead with your installation!
However - this may mean that you will be unable to boot to your Windows 7 without configuring the grub properly. Grub may detect your Windows installation better than the installer. This doesn't mean you'll lose any data, of course, it just means that you couldn't boot back to Windows 7 without proper configuration of the grub bootloader.