For Windows 7 Microsoft offers ISO downloads on their site, but only if you have retail Windows 7. If you have preloaded Windows 7 on your PC, MS refuses to offer an ISO download, and instead tells you to contact your PC manufacturer. You have to give the product key of your Windows 7 (retail) in order to download the ISO.

Then again the OP has preloaded Windows 8/8.1, so I don't think she can download any Windows 7 ISO image from the MS site anyway. The only option would be to download some pirate version I guess, as MS shut down that digitalriver site which earlier offered Windows 7 ISOs (there might be a mirror though which is still alive).

In case the OP wants to clean-install her Windows 8.1, then she should create a bootable Windows 8.1 USB or DVD-R installation media with the Microsoft Media Creator Tool. Here is the Finnish page for it, as I recall the OP is a Finn living in Switzerland.

http://windows.microsoft.com/fi-fi/windows-8/create-reset-refresh-media

I presume this is the English page for the same thing:

https://www.microsoft.com/en-us/software-download/windows8

This is because the OS locks the primary drive so you can't make major changes while the OS is running. If you try to run chkdsk/scandisk, it will ask if you want to schedule a check instead of performing one.

If you wanted to expand the C: drive after deleting the D: drive, then you can do it, but you're better off booting from a liveCD. Although the software I'd recommend (Bart PE & a good drive utility) probably won't work with today's computers.

Alternatively you can mount a drive to a empty directory, so you could make a c:\games directory and mount the drive to that in theory, however how well it works I'm not certain, I'm more familiar with Linux mounting than windows for that type of feature.

I've always used the freeware version, which may or may not be 1 or 2 versions behind. Licensed as a registered copy. Or registered freeware? Comes packed to the brim with features though. If I were hunting for a partition manager to purchase, it's the one I would go with.

EaseUS Partition Manager seems pretty comprehensive too. Another one they host as a giveaway once in a while. The cool thing with EaseUS is that most of their programs come with the ability to create a WinPE disk. Meaning you can run it at boot before Windows (or any OS I assume) loads up. Very useful in a case where you would want to manage the C: drive or any drive with an operating system that can't be managed because of programs running.

Speaking of that! MiniTool Partition Wizard actually will do that on it's own if you're managing a partition that's running an OS (OR) physically moving partitions. It can take a while, but I'd sacrifice time knowing that it's doing it's job correctly and efficiently.

A lot of people I refer don't like the idea of it, saying there's a lot of crapware and adware being given away, but honestly, I haven't had any problems with software from Giveaway Radar or mostiwant. Of course, I'm also very picky in what software I choose to download and I know the steps to take during install to avoid installing unwanted applications. IObit's software has also been a worthwhile endeavor imo.

If you're worried about spam in your inbox, just create a junk e-mail address :) I have one mostly dedicated to freebies :D

One word of advice though. Stay away from Glary Utilities. Running boot-time defrag with that got my computer stuck in a 'boot lock.' And their customer service is almost traitorous. No sympathy or any type of compromise from them as far as their faulty features go... in case you're looking into ze freebies.

I've had great luck with:
-IObit
-MiniTool
-EaseUS
-O&O Software

Summa summarum, or my takeaway from suggestions and analyses:

- C: is "locked" because the OS boots from this partition - good old fashioned installation disc will not be plausible to find, I suspect, so an external drive to boot from would be needed.

- Internal tools (Win 8.1) have not been very helpful, but this MiniTool seems well endorsed. The free version does not have "merge" functionality though!

- Will probably upgrade to Win10 first, then consider this issue. Only Microsoft tried to smuggle this thing as part of system updates, when my settings dictate I choose what I install (plus it was a hidden folder), so angry with Microsoft for the moment, because that was really shifty, I find.

THANK YOU all that read and posted! :-)

I think I know why now: the OS boots from C - and that is the core issue. I will see if installing Win10 per those Slate "privacy etc" recommendations will maybe be helpful for this too.

I've been on iMac for probably close to ten years before my current main gaming computer, so I have been implementing Windows partition (often painfully) myself, and not used to the off-the-self features.

Sorry, I was not so clear. I've been an iMac fancier for quite some time, and my current primary gaming computer is the first "Windows proper" for a long time, and I feel a bit alien to it. (obvious from this, right)

My iMac is still there for pre-current console generation, with Windows 7 from proper installation disk, and all, but the video card consigns it to older stuff.

Based on help and comments here, I know now it is the issue of OS booting from C-partition, and therefor C-partition being off limits.

If I want to address it, I need to boot from an external drive.

For my next eventual rig, I do see the advantage of building the computer up, though, I admit.

I have never really enjoyed any tech stuff, perso - I am quite ill motivated and not very good at it. My bro meanwhile is generally quite the capable tinkerer, and a generous soul to siblingly requests, and otherwise too. I must ask him to consult me, once my HW becomes obsolete.

But you've been insightful, for sure - me less clear. Thx for that - I think (hopeful smiley here) I know what to do.

If this is how your partitions are layed out, you won't be able to extend C without 3rd party software. You can extend the system volume, but there must be unallocated space AFTER C, you can't do anything with the space before C. The unallocated space must also be adjacent to C. You would have to use software to move C and then you could extend it.

I've used GParted (http://gparted.org/) in the past as it is free. As for not being able to delete D, the command line tool (diskpart) is a bit more flexible.

EDIT: And always back up your data before trying to modify anything.

Thx for posting, ncs. I probably cannot be the only one hating this limitation.

Only it is a feature that I am a bit cold and bothered about. I know Windows is super successful, and off the self for many of us a meaningful way to have a PC.

Only I think here MS should inspire from Mac to allow unified (large) hard-drive for those whom will tick the boxes.

Well, windows only needs two partitions, one recovery (~500mb) and the rest is the famous C drive.

Anyway, if I understood correctly, you have:

UNKNOWN | UNKNOWN | UNKNOWN | D: | F: | C: ?

Because the oreder is really important. You can always boot on a live iso of gparted, remove D and F and then expand C but gparted would move all your data to the beginning of the part which can cause a lot of issues and file corruptions. The best thing that I can suggest is: make a recovery cd, delete D, F and expand C using gparted, wait for the process to finish (4/5H the last time I tried it), reboot, enjoy your "Cannot boot", boot from the recovery cd, "repair" windows (reinstalling it using the custom option is the best thing because it will move all your old data to a Windows.old folder), ????, profit.

The French are considered both elegant and intellectually vigorous within Europe. In case this might have just about escaped you. :-D

Don't blame french people, blame my english :'(

Your English seems fine!