what have i done now

hi everybody.

bit of help needed to start off with if you please.

i have a ds lite with a micro sd and a super key , afte d/ling a few games that wouldnt work i read on hear after a search that i would be best of updating my firmware which i have done but now when i turn the ds on i get the initall h&s screen then both screens go white.

so i formatted the card again and tried to recover the old firmware and still same.

been trying to sort this all afternoon/evening now so any help is VERY MUCH appreciated


thanks