Hi guys! I have a PC with an Intel Pentium 4 1.5GHz, on an Intel D845WN Motherboard. The H.D.D was a Seagate 20GB. I have a Geforce4 MX440 (64MB, AGP8X) Graphics Card and a Creative Sound Blaster Audigy Live 5.1 Soundcard. The PC contains two optical drives, a Samsung 32x CD RW and a Samsung 16X DVD ROM Drive. Recently I bought a Seagate Barracuda 120GB H.D.D and connected as secondary slave. My 20 GB H.D.D is secondary master. CD RW is primary master and DVD Drive is primary slave. After connceting the Barracuda I am having strange problems like suddenly hanging the computer and missing the new hard disk on restart. What will be the cause of my problem? Is there any incompatibility? Please help me. My SMPS is 300w. And I have installed two additional cooling fans for my cabinet.