Windows 7 - Change Windows 7 windows border background pattern

Well I notice that their windows border have a pattern and after cleaning up my HDD i found this:http://img594.imageshack.us/img594/2539/971n.png
I don't even know where did I get it but I want to know is there any way to modify it?

yes there is a way of modifying it

If you can get the program Restorator (I use the 2007 version) and use it to open an .msstyle, you navigate to the left pane folder called Stream you'll see an image similar to the one you posted and the part I mostly modify is the "window"-like image.

I've attached two pictures so you can see in one; the restorator program that edits the aero background image and an example of one msstyle i did myself

I will try to remember exact details of how I did this for you and get back to you if you haven't found out or been told by then!