Is there a possibility to delete W8.1 folders and install W7

I have had numerous problems since installing Windows 8.1; the most frequent being the BSOD.
The specs for my desktop is available.
These are screeenshots of the internal HDDs connected to my laptop.

https://www.flickr.com/photos/131515492@N04/17501423789/

https://www.flickr.com/photos/131515492@N04/17655271226/in/photostream

https://www.flickr.com/photos/131515492@N04/17655271206/in/photostream/

https://www.flickr.com/photos/131515492@N04/17501423769/in/photostream/

I want to know if one really needs to uninstall the whole W8.1 with all the downloaded programs or if one can remove a few folders from windows 8.1 and install W7 in another partition?

 

If you want to add Win 7 to the system you don't need to mess about with Win 8 at all. Just create a new partition on the Hitachi and install it. That will give you a dual boot.

 

Also, you did not mention the brand and exact model. Before you start, you need to see if Windows 7 is supported on the computer. If the manufacturer doesn't supply driver, you may be very disappointed when some hardware doesn't work. If that is the case, you will be glad you still have 8.1 installed as a usable working OS.

 

Thank you for the responses.
My desktop has been upgraded over the years. Most of the parts have been replaced. I have updated my signature to indicate the make of the HDDs.
I see the screenshots do not display well, so I have uploaded them to a different site. I hope they display better now.
http://i261.photobucket.com/albums/ii62/avz10/Image%201_zpssfxg1a3c.jpg
http://i261.photobucket.com/albums/ii62/avz10/Image%202_zpsmwlw02bd.jpg
I had Windows 7 initially installed on the system. The motherboard was changed prior to installing Windows 8.1. I did however changed my one 160GB HDD recently and replaced it with the 500GB Toshiba.
I have never used a dual boot system and will read up about it (unless someone has a link to a good site)
Thanks again

 

Your disks remind me of the electrics in this old house of ours - no semblance of organisation following the endless addons and modifications over the years, but somehow it still works

Before advising we need to get a fuller understanding of your present situation so can you post (using the Manage Attachments button) a pic of your disk management snap-in that shows the full picture, as in the this one -

 

This is unfortunately impossible, as Windows does not start. It gives the error message on the BSOD "System Thread Exception Not Handled" error, I therefore cannot access Disk Management.

I took the HDDs out and connected them to a laptop and took the screenshots from the laptop, using Mini Partition Wizard.

As I have had so many problems in the past months with my PC: struggling to boot, giving me either blue or black screens, I just decided that it is time for me to take a step forward to W7 and hope that W10 will give me less problems.

Apparently, this error message is related to the updating of drivers and I have already downloaded most of them from the manufacturers' sites. I have not yet installed them, and they are still on the laptop.

That (installing the drivers) I will do and suppose one can do that without the desktop fully started up, but in the past 2 months, I have mostly been working on my laptop, as I think the desktop was non-functional for about 6 out of 8 weeks. If it does not want to boot, then the problem would be with the mouse and keyboard,this is the 3rd keyboard and mouse that I have bought in the past month.

I suppose that once I have updated the drivers, everything will be fine (never seen any yellow exclamation mark in Disk Management), but I have just had enough of never being sure when the next calamity will strike.
I do lots of video editing as a hobby, but this has come to a complete stop. (The desktop just has better hardware, an i5; 8GB of RAM, etc.

The bottom line- for years, I have had the minor problem, but now it seems like an avalanche. I just want a fully functional desktop. I think W7 can give me that.

 

What version of Windows with a COA/serial number is on the case? That will determine what the computer was meant to handle.

What authentic MS discs do you have to do clean installs?
Or did the computer come with any restore and recovery discs?

The answer to those questions will determine what you can do, which may be way different than what you want to do.

 

Have you tried starting in Safe Mode, tapping F8 at boot?

@plodr - the OP has had a new mobo recently so the case sticker probably won't help.