Hard drives won't work together?

[FrostBite]

Was fine this morning, went working on the case, and popped the hard drives back in. Now if I plug in both, only 1 will work. Both work, but just not together. Any idea what is going on?

 

[defakto]

check jumpers, if any are on cable select, set them to appropriate master or slave instead. Some drives don't play well with cable select *STILL*

 

[Ice Czar]

and make sure that the master isnt set to Single by accident (Master without slave)

alternately, try cable select for both

 

[IceDigger]

Definetly a jumper problem.