Change

[plgladio]

Is it possible to change the logo or add new logo in the system properties dialog box. with or without using tools.

[kukris]

If you mean the logo on the bottom left of the computer information, that's just a bitmap picture located under

windows\system\oemlogo.bmp

You can replace it with any picture you like as long as it is a bitmap file and you have to consider the dimensions. If you choose a too large picture, then it will be cut off.