Diablo 2 expansion patch 1.12 works but 1.13 doesn't?

I recently have gotten back into Diablo but whenever I try to play I get an error message from B net. And for some reason if I'm using patch 1.12a my bnet will load but it updates it to 1.13 when I do this and it stops working =( somone help and please reply in english. I'm no computer genius.|||your install may be missing some of the large mpq files from the cd's

copy these files from your orig cds to your d2 install folder

D2XVIDEO.MPQ

d2xtalk.mpq

D2XMUSIC.MPQ

d2sfx.mpq

d2video.mpq

d2music.mpq

d2data.mpq

d2char.mpq

d2exp.mpq

d2speech.mpq