Nintendo ds lite

try compressed air.
more then likely its a hardware issue. try getting an R4DS card and download games from www.filestube.com if you dont want to repair it.
you can have 50+ games on an sd card and not have to lug around all those games anymore

your DS may be too old to read the card... I got the "New Super Mario Bros" and my old DS wouldnt read it. when i tested it on my new one, it worked just fine. of course, it could also be the ds card slot. here is a website that sells replacement items. i would look up step-by-step instructions on how to replace it before you try anything.

http://www.nintendorepairs.com/parts/index.html

where can i find downloadable dsi. menu.dat
and dsi menu.sys please

clean off your games

You can play multiplayer games with a Nintendo DS Lite even if you don’t possess a copy of the game. If one of your friends has a multiplayer game card, they can use their Nintendo DS Lite as a host for the game session and you can join the multiplayer game.
jQuery('.intro .thumbnail').each(function(i,e){ jQuery(e).find('img').one('error',function(){ jQuery(e).remove(); }); });
Things You'll Need:

• Nintendo DS Lite

Using One Card to Host the Game
1. Step 1 Look on the game’s packaging for the "Multiplayer" icon. If the game requires only one player to have a copy of the game, the icon will show two DS Lites: a DS Lite with a black screen transmitting waves to a DS Lite with a white screen. Below the two DS Lites is a range of numbers which indicates how many players the game can support.
   
2. Step 2 Put the game card in the Nintendo DS Lite that is acting as the host for the multiplayer game session and start it up.
   
3. Step 3 Have the other players turn on their systems. They will use the main menu screen to access the "DS Download Play" icon. They need to tap the icon to begin downloading the game information from the host DS Lite.
   
4. Step 4 Begin playing when all of the systems have finished downloading the game information from the host.
   
Multiple Cards for Multiple Players
5. Step 1 Look at the "Multiplayer" icon. If every player in the game session needs a copy of the game in order to play, the icon will show two DS Lites, both with black screens, transmitting waves toward each other. A range of numbers is under this graphic and indicates how many people can play at one time.
   
6. Step 2 Read the game's instruction manual on how to set up the game session. The steps required vary by company and sometimes by title within the same company.
   

*reposted from ehow.com

Insert the game BEFORE you turn the DS on.

the contacts where the game go got dirty or broken!, u will need to get it repaired

You turn off your DS, take your game out & blow on the game cartrige and where the game actually goes INTO the DS.If this doesn't help, leave toyr DS for a few days and try the blowing again.
Hope this helps

their are 3 solutions but i cant asure that it will work
1. maybe when they play ds games like pac n roll the ds cardejects for some reason so sulution 1 is put tape ontop of the ds gamecard slot while their playin a ds game
2 maybe when they play a gba game the game pak is being hit by their chests or bellies so the card is moving a bit and the game freezes so put a big distance between the ds and the chest or belly
3. dont wiggle the ds alot and do you drop it often because if it is dropt often the ds will freeze often

Remove the game cartridge and try it again. During the boot sequence is when the DS tries to activate the port and check of it is going to load a game from there, or use the internal sequence and load the menu.