Maxtor SATA

I am having trouble having my maxtor sata 200gb hd showing up I have checked thew bios but cant get it to stay showing up in My Computer

The only way I can get it to show up is to turn off the computer and the unplug it and turn back on and then shut down again and plug it back in and turn on again and it will show up but then if I have to restart it will disappear:(?

Any ideas of what I can do to correct this problem?? I never had this problem untill today when a comcast tech came out to set up my cable tv and internet. I just moved over the weekend and had everything tranfered from one place to another

thanks for any help