Nikon Capture NX will not open black and white jpegs

Open the "Shooting Menu" by pressing the Menu button. Press the right Multi-selector and then scroll up or down to "Image Quality". Press the right Multi-selector and you will see the various choices for JPEG and NEF combinations and quality, make your selection by scrolling up or down and pressing "OK".
As for converting you NEF photos to JPEG; you can easily do that in one of several ways on your computer. If you are using Lightroom or Photoshop, all you have to do is open your pictures, select "Save As" and use the pull-down menu to select JPEG and save. If you do not have that program, there are several conversion programs available on the Web; manu for free. I use a program called BatchConverter on my Mac. There are similar programs of PCs.

hmm..well..that is a little weird..can you supply the operating system for your mac, and also the rev level of image capture?

Does your PC recognise the fact that you've connected your camera?

Try uninstalling Capture NX2 and then reinstalling, if you still have the Installation CDs.

Guide to recover deleted photos from Nikon D70?
Connect Nikon with PC
Using a USB cable or putting SD card into an SD card reader to connect Nikon with Computer.
Scan Nikon d70- Running the Nikon Photo Recovery,you can choose Nikon media drive and click "Start Scan" for scanning
Recover deleted photos
After scanning, you will see all recoverable media photos and videos with file type. At last, click "Recover" to recovering deleted Nikon D70 photos.
This Photo Recovery also can recover all photos files from Nikon D3100 like JPEG, BMP, TIFF, GIF, etc. Support all Nikon camera.
For full details please refer to Nikon D70 Manual.- https://guideusermanual.com/product-name-d70-manual&po=4425&lang=English

Nikon Capture NX 2 is a commercial program, not a free program. However, there is a free 30-day trial version available at
http://support.nikonusa.com/app/answers/detail/a_id/16682/session/L3NpZC9FclVoVG5Tag==/sort/1,2/r_id/116678/sno/1

Capture NX is not supported on Windows7. You'll have to upgrade to the current version of Capture NX2. If you're already using an older version of NX2, the same applies.

Here's the manual (free download)
http://safemanuals.com/user-guide-instructions-owner-manual/NIKON/D40X-_E

Black and white is a menu option......

Select > Shooting menu
Select > Optimise image
Select > Black and white

Page 68 of the manual has full details of other options.

Note that you can also change photos to black and white in good post processing packages (such as Adobe Photoshop), although invariably there is some quality loss over original capture.

Please open the "paint" from"start/all pograms/accessories/paint".

one when you open the paint, click on file and select the option scanner and camera wizard.

when it open click on scan and when scan get complete click on file and "save as " and select the formate "jpeg" and save it.

Open Jpeg in a paint program or photoshop, add color and save as *.jpeg, so you keep the original

Normal 0 Double Click on this site
http://www.free-codecs.com/AMCap_download.htm
to download the Free AMCAP Video Capture Program.
AMCap v9.20 AMCap is a small yet fully functional video capture application compatible with Microsoft DirectShow. It is based on the sample AMCap from the Microsoft DirectX 9 SDK. AMCap supports still captures to BMP, JPEG and PNG formats and it remembers your Video Input, Video Standard and Video size settings from previous session. It has some nice features like multimonitoring support, zooming, aspect ratio and deinterlacing features.

AMCap is a small and effictive piece of software and definitely worth trying. Hope this will help. Bud