For the scrollbar arrows, in SKS, go to Controls > Scrollbars on the left side. On the right side, you will see the file for the scrollbar arrows.

For the "three light blue lines in the middle of the scrollbar as we see in Windows XP theme", in the same section of SKS, go to Scrollbars > Horizantal Scrollbar Tray > Horizantal Scrollbar Thumb-Small. Do the same for the vertical scrollbar.

Hope this helps

Those Arrows are skinned using Controls > Scrollbars > ScrollbarArrows.bmp

The other is the Controls > Scrollbars > Vertical \ Horizontal Scrollbar thumb > Glyph image...it is a few entries down in the Scrollbar thumb attributes list.

Dang...it wouldn't let me edit.

Anyway, for the scrollbar arrows, when you get to the scrollbar arrows on the right, click on the glyph image > scrollbar glyph image...those are the arrows.

If you by chance are using the trial version of Windowblinds, the scrollbars will not be skinned (that's intentional).

I don't know if SKS free can tell that & disables scrollbar skinning as a result (I have always had an OD subscription), but if it doesn't, there are 8 images that comprise the scrollbar skin - the endbuttons (usually scrollbararrows.bmp or arrows.bmp), the endbutton/arrow glyphs (if used, not usually needed), the 2 scrollbar tracks (vertical & horizontal, usually scrollbarshaftvert.bmp & scrollbarshafthorz.bmp), the 2 "thumbs" or sliders (vertical & horizontal, usually scrollbarthumbvert.bmp & scrollbarthumbhorz.bmp) and the 2 scrollbar glyphs (often used, the "3 lines in the middle" of the sliders, usually scrollthumbglyphvert.bmp & scrollthumbglyphhorz.bmp). You can also have a glyph in each track/shaft image, but I don't think I've ever seen them used so I didn't count them.

The actual names will vary from skin to skin so you'll need to select individual images from the SKS preview or Explorer to see what they happen to be named.