How to create - or convert - partitions in a Legacy MBR/BIOS setup

Thanks @Ghot .... you're spot on (in your post #28 - this discussion is moving faster than I can type!). To install Linux and dual boot this laptop (like my others) I do indeed need more space. And I need to organise the partitions accordingly.

In terms of space, I know I can shrink the C: (sda3) partition where Win10 sits as the current OS. How much space I can get from that is not yet clear, but freeing up 40-50GB ought to be no problem. I have yet to delete all the Windows.old files left over from the upgrade from Win7 (and which are sitting within the Win10 OS on the C: partition), so that should give a bit more space - possibly some 20GB? I reckon I ought to do that disk cleanup and shrink the C: partition before I start reconfiguring. If I can safely delete or remove the "old" Recovery partition, Q: (sda2) as well, then that offers yet more space.

Which was, in a way, where I started with this thread: I needed to know which if any of the existing partitions I could delete (or indeed reformat - since Linux will need ext4 partitions). And because of the limit of four primary partitions I reckoned that I needed to reconfigure somehow. Either I have to enable the creation of an extended partition (which means 'losing' one or more of the existing ones - but which?). Or I needed to empty, and reformat, one - or more - of the existing primary partitions (hence my curiosity about the PW option of converting a primary to a logical partition).

The consensus seems to be that I can without problems delete both the System Reserved (D:) sda1 partition and the "old" Recovery (Q:) partition at sda2. That - plus any shrinkage of the main C: partition (sda3) - ought to give more than enough space for me to create a new - reformatted - partition into which I can install Linux.

So it looks as if I will have to decide how radical the surgery should be: delete both D: (which is tiny) and Q:, or just delete or convert Q, before shrinking C: and then create a new partition for Linux.

Ah, choices, choices.... @topgundcp in post #6 said what he would do if it were his system. I'm open to all suggestions!

And yes - whatever changes I eventually make, I will be making a backup image first (I've used Clonezilla before, but am equally ready to give Macrium a try).

I have just tried the pwfree9.iso which claims it doesn't support server os. I am not using server os. Very odd.

I also tested the pwfree9.1-x64.iso which also refuses to load claiming a server os.

I will have a go with the pwhe811.iso

edit: same message

"This bootable cd does not support windows server"

Happily, The paragon bootcd_x64.iso runs fine

Thanks to all who have joined in on this thread.... and special mention perhaps to @Ghot, and @topgundcp, who helpfully focused on exactly what I could or should do in terms of changing, reconfiguring or deleting some or any of the existing partitions on my disk.

I've been trying to take stock of where we've got to.

The thread took a side-turning into exploration of what versions of what imaging software might be available and what they might do... Macrium, Partition Wizard, even Aomei. That was prompted by the basic advice (which I accept) that taking a disk image before messing with partitions is very sensible. I totally agree.

There doesn't seem to be a clear or universal consensus on which or how many of the four existing partitions I could delete. All are agreed that C: (where Win10 resides) should stay - obviously. Most think the unlabelled partition is the Win10 recovery one, so should stay. And most also think Q: (the other 'Recovery' partition) is for Win7 so now obsolete/unnecessary. I'm still nervous about wiping D:, the System Reserved partition. If it wasn't needed, why did the Win10 upgrade-install create it?

The other thing I'm still nervous about is moving the C: partition. Third party tools can do it. But lots of people say that Windows doesn't like the start of its 'active' or bootable OS partition to be moved (and won't let that be done in Disk Management!) , because the boot process then can't find it. Which gives me a problem if I delete Q:, because I would then want to move C: to the left. I may just (as some have suggested) try it and see, with a backup image available in case it all goes wrong.

Meanwhile it has rightly been pointed out that all this juggling of partitions, and the idea of deleting or shrinking, is because the 256GB disk is tight on space for running two systems (Win10 and Linux Mint) in dual-boot.

And by chance I have found a totally different - and radical - idea which might offer an alternative way to go.

The Lenovo T430 has an empty but easily accessible slot which can take an mSATA SSD as an additional drive. So I have the option of putting a 256GB or even 512GB mSATA SSD there. I can then install Linux Mint separately on that, keep the existing drive (C: and the others) more or less as-is as the location for Win10, and not have to worry too much about freeing up space on that drive to make room for Linux. Saves the uncertainty around messing with the existing partitions.

As I like simple solutions, I'm attracted to this one. So I've ordered an mSATA SSD.

I may still have a go at revising the partitions on the main drive. But it's not as vital a task as I had thought when I started the thread.