Ds wont find games on r4 card

Go to www.r4ds.com download & unzip the kernel. This will create a folder with the operating system.Copy these files to the root of the SD card (There should be 2 files & 2 folders) After this, copy the .nds files also onto the root of the SD card, and the games should be visible & playable when you turn on the DS 
NOTE: this will not work for the Nintendo DSi 

There's a great tutorial on http://www.dscardworld.com with pictures and links to all the official software.

If you suspect that you have unstable fake clone version you can get a genuine card there too. I managed to find this site after I got burned at a few others. Loved having my emails responded to because I had loads of questions, and they were quick to ship it.

Best of luck!