Start up problems after drive changes - Non urgent

Hi, this isn't really urgent at all, but thought it was better placed in here then anywhere else.

Ok, the situation as it stands is like this, i bought a dvd writer a while ago and installed it with no problems, but now i've decided i would like to put my old cdwriter back in to my pc too (burns cdrs faster, spread the wear and tear over 2 drives etc.. and general just stop it from being sat on a shelf) And this is where my problem starts, i'm using an Abit IC7 mobo with 2 ide and 2 sata available, my main hdd with all my operating systems has always been plugged into the first sata, and i used to run the first ide to both my dvd writer and a spare ide hdd for storing back ups of important info. But now that i have installed the cd writer again i've put both drives onto ide1 as a master and slave and given the spare ide hdd it's own cable going to ide2 on the mobo. Everything would start fine before with bios showing my main hdd on ide channel 1 and my dvd writer and spare hdd on ide channel 2. but now when i start it detects all the drives fine and goes through post but then doesn't boot at all, just stays at a blank screen. On going into bios it shows my dvd/cd drives on ide channel 1, spare hdd on ide channel 2 and now my main OS hdd on ide channel 3. i've checked and set hdd priority to the right hdd but still nothing. other than that i dont know what to try and don't want to mess things up in bios doing so.

Any ideas?

thanks
bres

Sorry to bump this but anyone? any ideas?

Im sure you've checked, but just in case, have you looked in the bios for boot device order???

yeah, i went into bios and made sure that was all ok after i changed everything. Only thing i can think of is, could i need to update my bios as i'm still using the original bios version from when i bought the board due to the thought of, if it isn't broke, don't fix it. What do you think? likely to be the problem? Never updated it before and the abit sit is a little confusing on the subject in my opinion. How would i go about it too if it was the problem?

cheers