16.04 - Install ubuntu with existing windows partition

I wan't to format my windows(7) pc and install Ubuntu 16.04 , But I have 4 partition that I can't format anyhow. How can I Install ?

There are a couple of issues you must address:

• If I understand correctly, you want to replace Windows with Ubuntu, but preserve your existing Windows data on some partitions. Chances are these partitions use NTFS. If so, it's very inadvisable to continue using those partitions as-is in Ubuntu, the reason being that there are no good NTFS maintenance tools for Ubuntu (or any other Linux distribution). Thus, when the filesystem develops problems (note: when, not if), you'll have to jump through extra hoops to fix the problem. If, OTOH, I've misunderstood and you want to keep a Windows installation while dual-booting with Ubuntu, then continuing to use NTFS for your personal data isn't so bad, since you can always reboot into Windows when you need to repair the NTFS volumes.


• You haven't said whether the computer uses BIOS or EFI firmware. The details of any OS-installation procedure will vary depending on whether the computer uses BIOS or EFI.

Overall, I'd say your best bet is to back up the data you want to preserve to a suitable backup medium -- perhaps an external hard disk. You can then wipe your existing disk clean, install Ubuntu to it in whatever way works, and then restore the data from the backup. Alternatively, you could buy a new disk, install Ubuntu to it, copy the data from the old disk to the new one, and use the old disk as a backup disk. (The details on this approach would depend on whether there's room in the computer for a new disk or if you'd need to swap disks and put the existing internal disk in an external enclosure.)

Concerning the BIOS-vs-EFI issue, see this question on SuperUser.com, and my answer to it. Manufacturers switched rapidly from BIOS to EFI in late 2011, but there were some stragglers after that point, and some EFI pioneers before then. Most EFIs enable installing OSes in BIOS mode, but as a general rule, it's best to stick to the firmware's native mode, which means EFI with most modern computers. (Some early EFIs were flaky enough that they can be exceptions to this rule, though.)