repair tool

No way to answer that because you have not given a link to the tool or stated the tools name.  The 0x8007007A error most often happens when persons are trying to send pictures. Is this the same with you?

Generally Repair Tools are Junk and not something we recommend here. Most of the time they create many more problems than possible "fixes".

There are many websites with the word Wiki in them but what you have listed is not one of them. In order to get the correct address to a website go to that web site. Then click in the address line of the browser. The address will then be shown in blue, right click and choose Copy. Then come here and place your cursor into a reply and right click and choose Paste. The correct address will be placed into the post.

The error you listed, 0x8007007A is a very common error people receive when attempting to send pictures using WLM. Much of the time it is because they are sending them incorrectly often time as an album not a single attached picture.

Try this:

Open a new mail to send and choose who the mail will go to.

Next Click on Insert.

Now click on Attach File (Paper Clip Icon).

Navigate to the Picture you want to attach, Select it. It will be attached to your email. If you want to send more than one picture click on any image that you want to Send, Hold Ctrl Key and Select other Pictures too.

Are these your personal pictures or pictures from somebody else or a web site?

Windows has a built in repair option for programs like Windows Live Mail. If you feel it needs fixing, though likely it does not, you can use that built in fixer.

Go to Control Panel -> Programs -> Programs and Features.
Right-click on Windows Live Essentials 2012 and select Uninstall/Change.
When the dialogue box opens, select Select Repair all Windows Live programs.
Now you have to wait until the system finishes the repair process. Once this is done, restart your PC.

You cannot compare an online email program like Yahoo or others to a program like WLM that is installed on the computer. they work entirely different.

By the way, the program you asked about that is listed on that wiki errors web site gets terrible reviews. In the end it is NOT free. From all I have found it is one of those Scan for Free programs but PAY for Fix and it costs anywhere from $39.00 to $250. I found that on numerous web sites. Many users reported serious damage done to their operating systems by this scam program. More than one were forced to reload their operating system because of damage done by this program.

Wiki-Errors.com is also not a web site I would recommend either. I surfed through it and found some really questionable recommendations. Their explanation of your error was really incorrect just giving a very general piece of information of what error codes are;

If you want to know the actual cause of an error code and what it means then just type the error itself into google or duckduckgo and the top recommendations you will receive tells you that error code refers to an email error.

Of course you can do anything you wish. This error is a Known problem with sending pictures with WLM the way you are attempting to do because the Send To request is, for some reason, looked at as an Album once it gets to WLM and you cannot send an Album via WLM. This is well known and has been for several years and cannot be corrected and WLM is not broken it just cannot use the Send To order.

Here is the very first results received when doing a search using only this criteria "0x8007007A error" without the quotes of course;

I never ever received that Wiki-errors.com on my search results. It may have been there on page two or something but I don't go farther than the first one or two recommendations on a search like that.