Brother XL--2600 Sewing Machine not picking up Stitches at all!

First thing change your needle, now clean out your bobbin case with a brush and oil as your manual instructs. Part of the broken needle may be inside your machine

try changing the needle
make sure the bobbin is inserted correctly
make sure the bobbin is not warped
make sure the bobbin is turned the right way in the bobbin case
make sure the top tension is adjusted correctly
make sure the top and bobbin thread is the same

try adjusting the top tension and see if that help the bobbin stitches
to look normal
here is a 2 links for a free manual, check and see with is the right one
for the machine

http://www.brother-usa.com/ModelDocuments/Consumer/Users%20Manual/UM_XL_2600_2610_3500_3510_EN_206.PDF

http://www.brother-usa.com/ModelDocuments/Consumer/Users%20Manual/UM_XL_2600i_ENES_1478.PDF

No, it seems like you haven't listened for the click of the bobbin locking in place when you put it in.

All machines have a bobbin case, if you have a drop in bobbin it drops into the bobbin case,

try changing the top thread tension to 3 or 4

also rethread the machine just in case the thread is hung up somewhere

take the bobbin out & put the bobbin in reverse of what you did before

you said you changed the needle, check to make sure it in correctly,, the flat side goes to the back of the machine, push it all the way up before tightening the screw

Don't use it. The bobbin cases are designed to work with the specified bobbin size, see if you can track them down on Ebay or through a sewing machine dealer in your area.

Check the bobbin tension and that the thread is tight around the bobbin. Make sure that the bobbin is in the right way around - the bobbin thread should double back on itself coming out of the bobbin holder.

This is easily solved. Before you start sewing make sure your upper and lower threads are long enough for you to hold before lowering the presser foot. If these threads are too short they both get carried down into the bobbin along with the fabric and cause a big tangled mess. Always hold your threads at the back of your work with your left hand then lower your pressure foot and don't release the threads untill you have taken several stitches. Keep holding these threads during backstitching at the beggining of a seam too. Works like magic.