Hello! How do I use folder icons in png format and other formats in that matter? It couldn't be found where I try to customize the folders.

Vista doesn't support PNGs for folders. The easiest way to do this without installing software is by doing the following:

Convert your PNG here: http://converticon.com/

Then use the .ICO by doing the following:

• Right-click folder and click properties
• Under the Customize tab, click Change Icon
• Browse to where you've put your converted icon and double click on it
• Click OK

Are there any offline converters available for free?

so far, I've found some offline and free converters, but every time I convert a PNG into an ICO, it reduces the quality so badly that the icon gets all pixelated...so i just use converticon.com like Rich said