What can be deleted in Windows folder?

I need to free up more HDD space on my c:\ or Windows drive.

I installed Windows on a small SSD (128gb) and now after a few years of usage
I only have about 10-15GB free.
I only installed windows on that ssd and some programs.

How can I free up more space on my C:\

I have used a drive scanning software to identify space hogging folders and found following space hogging folders in Windows folder

These are the largest size folders (order from largest first)
-Installer (13 GB)
-winsxs (11 GB)
-System32
-assembly
-ServiceProfiles
-sysWow64
-Microsoft.net
-SoftwareDistribution

Now I know some folders contents (files) should not be deleted
e.g. System32

But what about other folder contents like these folders (2 biggest offenders)
-Installer
-winsxs
Can I safely delete the files in these folders?
Which other folder contents can I delete in Windows folder?
or in the C:\ in general?

What other options can I do to get more free space on a small size SSD?

I can't buy a bigger drive right now because the prices are still too high and I want to get a 1TB ssd when the price is right..

AddRAM said:

3 things you can do to gain space.

1) Turn off or lower the page file to 2 GB, with 16 GB I haven`t used a page file in over 2 years.
2) Lower the amount dedicated to system restore
3) Turn off the hiber file if you don`t use hibernation.

1) I moved my pagefile to another drive so that is not an issue.
Also turning off pagefile causes issue with some programs.

2) System restore is currently at 5% for C:\, how much lower should I go? I haven't used system restore for a while, should turn it off for c:\?

Edit: Thanks for this suggestion, good idea.

3) I don't have hibernation turn on, so no hiber file, because it is a space hogger.

Do u have any answers for my original post questions?

AddRAM said:

Well, something is wrong if you installed windows and just a few programs. I just did an install, fully updated and my programs and there is only 20 GB total being used.

I don`t even see an installer folder in my windows folder, so I`ve no clue what that is.

There is no reason to get a 1 TB ssd, a 250 GB is more then enough for windows.

SSD 850 EVO 2.5" SATA III 250GB | Samsung Solid State Drives

Yes, it is more than a few programs..
I was just trying to be brief.

I could say I have said I installed windows and all my programs in there..
But that would not be entirely accurate either, because I have installed some large sized programs on another drive.

But then people would just say
"Uninstall programs unused" which I know is an option..

I also didn't install any games on it though
e.g. Steam...

But my main point of the post was whether I could delete some of those folders contents as mention in my first post.

==
Yes 250gb might be enough for windows, but I already got 128gb.

There's no point in getting a new ssd to just double the space..
and then down the track needing to buy another new SSD...

500gb might be good too, but since I am going to get a new one, I might as well get a 1TB.

Also it allows some space for dual booting another OS.
-like Linux, OSX hackintosh.

Or installing some steam games that I want to speed up loading time.

So it is one 1TB for me.