windows editing tool for .avi

I would  have movie maker in my mind....
Free tool from Microsoft....
http://windows.microsoft.com/de-DE/windows/get-movie-maker-download

At least it does what you describe....

Another free Microsoft tool is..

Recommend by EE for editing Video Micro Tutorials..

Media Expression Encoder 4

DirkMare

Adding to Bembi
and english version, it's not a straight out cutting and then joining avi in WMM it takes a little know how.
You might need to see to a tutorial how to split each clip then simply go to file and save movie for choose from the many outputs each has a different size. I like the mp4.
How to cut out sections of a video with movie maker nice and simple
https://www.youtube.com/watch?v=LDEO2z3Eyxc
You will ret a lot of great infor from How to Geek on how to use Windows Moviemaker it's excellent
Turn Photos and Home Videos into Movies with Windows Live Movie Maker
http://www.howtogeek.com/howto/18003/turn-photos-and-home-videos-into-movies-with-windows-live-movie-maker/
If you get stuck ask away.

When installing windows essentials 2012, I get an installation error.

it says:
Couldn't update to the latest versions
Photo Gallery and Movie Maker
Outlook Connector Pack

Because there was a problem updating one of the programs, none of them were updated
Error:0x80040609
Source:soxe.definitions

any idea what is wrong

Have you had an earlier version on Windows Essentials or Windows Live on your computer?
You may try to remove it first, reboot and try again.

Sorry for the german link.... ;-)
As Merete said, you may only install movie maker, not all the other stuff.

http://www.microsoft.com/en-us/download/details.aspx?id=19652

I installed Microsoft media encoder 4 on to different laptops in the past week had no issues it takes some getting used to but it's a learning curve either way.

DirkMare

The only drawback with the free version of Microsoft Media Encoder 4 is that it does not support H.264, presumably because of licensing issues.  You have to pay for the "Pro" version for this support.  H.264 is probably the most commonly used High Definition encoding for web-rendered video at the moment.