There's 2 things that are possibilities:
1. Your R4 is too full. It means you have to remove some games.
2. If you have v1.19, then remove that and get v1.18. There's no such thing as v1.19.
This is usually a firmware problem, make sure you installed the correct firmware, and to the correct place on your memory card.
check your packaging for a website, or use the CD if it's the official R4DS
The "_DS_MENU.dat" file needs to go to the main (root) of your MicroSD Card, along with a folder that comes with your firmware/kernel.
Buy legal Nintendo DS games. (you won't get any other answers on wikianswers)
Nintendo - Dual Screen
because ds stands for dual screen
You go to the Nintendo DS settings and you pick the screen icon.
Nintendo ds is older, fatter, dark screen Nintendo ds lite is thin, bright screen so you can actually see and buttons are better
The DS in Nintendo DS means Dual Screen because the Nintendo DS has two screens. Or, it could mean Dream Scape, but Dual Screen is more likely :)
No, in fact, the clear screen protectors help to prevent damage to the Nintendo DS screen.
dual screen
No, the Nintendo DS and Nintendo DS lite have the same screen size.
you reformat it
No, the Wii is Nintendo's home console that needs a TV and the DS is Nintendo's Dual Screen handheld, which has a touch screen.
The Nintendo DS Lite has a brighter screen the the original Nintendo DS and it's slimmer as well other than that there are no huge differences