mnmbar

My dvr uses an ATA hard drive the first time it went out on me I purchased a new one and installed it with no problems. Now when I installed the new hard drive and when I plug it in the checking hdd comes back as no hdd...... I then go to the menu directory to see if I could reformat it but it can't be accessed because there is no hdd in system. Can any one help please??? The hard drive that I purchased is an Seagate ATA 250gb.