I finished repainting a Piper PA-28 add-on from here (it came with a paintkit) I have all the paint files BMP i put a texture file in the aircrafts FSX folder but no window shows up in FSX showing my repaint, how do I convert these files into a FSX ready format?

where can i download that?

If I'm reading this right you need to add your repaint as a new variation by editing Aircraft.cfg. The repainted textures should be in a new folder with an appropriate name. It should be named Texture followed by a period & then a suffix to identify it. For example you could name it Texture.myrepaint

Then open Aircraft.cfg in Notepad & add a new [fltsim.x] entry directly below the last existing entry. You can do this by copying the existing entrry & pasting it below itself. Change the number in the header to the next in sequence.  Point the texture= line to the new Texture.myrepaint folder like this: texture=myrepaint

Other lines will need editing. If you're familiar with installing repaints you should know the procedure. My Add a Repaint walkthrough explains the basic principle. http://www.simviation.com/lair/Repaint2002.htm
This is not much different in FSX. Use the Aircraft.cfg of any default aircraft as an example.

Once you get it working you can take a screenshot of your new variation in FSX. Resize it to 256 pixel width & save it as thumbnail.jpg. Pop this in the Texture.myrepaint folder for the image to display on the FSX selection menu.

You're welcome. The basic principle is just the same in FSX as in previous versions of FS.

nevermind, Found the right porgram 

WOOHOO got a new window option to appear apparently files still arent properly converted it was balnk, the aircraft is the piper arrow 3 on page 6 of the props downloads, so my new objective is converting the files = ],


(btw how do i save in DXT3?)

I just checked the aircraft out. It already has 3 variations each of flyable & AI Only versions using 3 different models, 2 panels & 2 AIR files. This is a tad complicated for a first attempt at repainting. IMHO

The main textures appear to be standard 8-bit (256 colour) BMPs. Depending on the graphics editor/paint program you're using to repaint the textures it should be possible to save in this format without using DXTBmp. The 16-bit Extended BMP formats like DXT3 & Extended 256 colour also appear to display correctly although I only have the FSX Demo to try them on.