Where can I install ubuntu if I have 4 primary partitions?

Question

I want to triple boot Windows 7, Backtrack, and Ubuntu.
Windows and Backtrack are already installed.

The problem is that both of them take 4 partitions: 3 for Windows, and 1 for Backtrack.
When I try to make another partition, it says I can't have over 4.
How can I install Ubuntu with this problem?

Note:
The 3 Windows partitions are PQSERVICE, SYSTEM RESERVED, and eMachines. I don't really know if I can delete one.

Answer 1

Hard drives are indeed limited to 4 primary partitions. Luckily for us multi-booters, if you create an extended partition, it can serve as a container for additional primary partitions. The problem is, since an extended partition counts as a primary partition, if you've already hit the limit, you would need to remove a partition and recreate it within a new extended partition. Since you said that your partition manager complained, it looks like you've hit that limit. So, my best advice is to see if you can safely delete and recreate one of your partitions. Your best option may be to do so with Backtrack's partition. If you have a spare hard drive, you could probably clone that partition to it and restore it back onto a new partition within your extended partition.

Unfortunately, that's the only solution I know of. More experienced guys can probably give some more insight, but hopefully this will prove helpful at least for now. Best of luck to you!

Answer 2

You have several options:

• Convert from a BIOS-mode to an EFI-mode installation. This will also convert from the limited MBR partition table to the newer GUID Partition Table (GPT), which raises the 4-partition limit to 128 partitions. The trouble is that converting Windows from MBR/BIOS to GPT/EFI is tricky; you may need to re-install. Also, older computers are BIOS-only; EFI became common only with new machines delivered in mid-2011 and later.
• Convert one or more existing partitions from primary to logical form. This can be done with my Fixparts program, which is installed in the Ubuntu gdisk package. There are caveats to its use -- see its documentation for details. Chances are you can convert Backtrack to boot from a logical partition relatively painlessly. Once you've converted one partition, you should be able to create additional logical partitions, although you'll have to resize and perhaps move partitions to get it all done. DO NOT convert the Windows boot partition; it must boot from a primary partition.
• Get another hard disk. This is the safest way to get another OS installed. If your computer is a laptop or really tiny one (like an Intel NUC), you might need to use an external disk.

Those are all the options that spring to mind and that I recommend. Which is best depends on your specific needs.