Desktop Model: Acer Aspire M5100-E5305A Operating system: Vista 64-bit LCD screen: DELL Computer has two hard disks, each 500 GB. First one with two partitions is running the operating system, second one just for data. Replaced the second 0.5 TB hard drive with a 1.5 TB disk. Tried to start the computer, no boot beeps, and a black screen. Both fans are running, the one from the source and the one on top the CPU, but otherwise the computer is dead. Put back the old second hard drive, re-started, computer is still dead, no boot beeps, no video output. Keyboard and mouse are dead too. Took out the power and held down the power button for 60 seconds, re-started, did not do any good, computer is still dead. Any ideas what I can do? Computer is back to its original hardware configuration, but it would not run, not even a bloody beep! Thank you, Colin.