My Toshiba Satellite 1805-S204 turns off when i'm trying to open DVD-ROM bay. Sometimes i can open it but than notebook turns off when i'm closing DVD-ROM bay. I want to disassemble 1805-S204 to find out whats happened, but i wonder what screws should i take out to get to DVD-ROM. Thanks.

I suspect, if you haven't got it working on the AC adaptor when this happens, that maybe the battery is low power. If it does it when the AC adaptor is being used then I think you are right, the DVD ROM is faulty.
Remove the battery and AC adaptor.
Remove the Memory cover.
There is a singel screw that holds the DVD drive bay in. Remove the screw and pull the drive out.
Replace the drive with and IDENTICAL model and that should be that.
Hope this helps.