Maybe, its hard to say, when is your other system due back?
If the problem is something small like an IDE cable, it would be a little annoying to pay for the postage (unless the supplier will cover it)
Are you able to get access to any other computers over the weekend (friends/family)
If your not going to have the chance to test individual parts for some time, then I would suggest checking all the connections again, disconnect the power and IDE cables and reconnect them, make sure jumpers are in the right place, and when your pretty sure there is nothing else you can test, then get in touch with them.
I use Ebuyer, now they are pretty good in terms of price, but delivery is a little slow and they take ages to test returned items before taking ages to return them to you, so for me, sending everything back to my supplier would take about 2-3 weeks before I got my (replacement) parts back.
If you have done everything you can do, and you don't have access to any other PC's, then your only choice is to get in touch with them and get it sorted as quick as.
But, how annoying is it when you have been waiting for your stuff to arrive, you spent maybe an hour or more building it, and then it doesn't work! :X
well im going to a friends house tommorow so a may take it with m eto see if i can get it too work there.
im not sure when the other system will back so it will probably be a while.
i bought the kit from komplett and the managed to deliver it early say i don t know what they are like with returned items, i may ask them if they think they may be dead
It just sounds like you haven't correctly installed the drives. Put the hard drive on the primary IDE channel (the first connector on the motherboard - usually labelled IDE0 or IDE1). Ensure it is set to "master" in the jumper configuration and that it is plugged in with the end of the IDE cable. Same story with the optical drive, but on the secondary IDE channel (the second connector on the motherboard). Do not place both on the same IDE channel/cable.