I have a 160 gb seagate SATA hd as a slave on my computer. One IDE hd is the master and another IDE as a slave as well. The computer boots fine but once it has been on for a period of time (30 mins to an hour) it makes a short beeping noise and the SATA hd just disappears. If you go to my computer it is no longer there and you can't access anything on it. If you restart the computer it comes back and everything is fine until it disapears again. I checked the drive for errors using the software that came with it and it found no errors. The drive works fine before it disappears. I have a 450 watt power supply so I don't think that would be the problem. Could there be a problem with my SATA controller and how would I check that? Any other ideas? Thanks a lot!