Well, Igor, you don't give us much information!
Let me guess:
You have a new computer now and it came with one hard drive attached to the
small, flat connector on the motherboard. (That is a SATA connector). You
removed the HD from your "old" computer. You attached it to the motherboard
of the new computer using a wide, flat cable to the suitable connector on
the motherboard. (That is an IDE/PATA connector.) Or, you attached it using
the second connector on the cable to the DVD drive. You also attached an
appropriate power connector to the drive.
Now, the drive can be heard to be spinning but it is not listed by your
computer when you look at Computer listing.
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Check on the old hard drive next to the large flat cable connector for a
block of pins. Make sure the jumper is covering the correct set of pins for
your setup. If the drive is alone on the cable, use the Single Drive
position. If on a cable with the DVD, use Slave position. There is usually a
label on the HD to indicate pin positioning. If not, consult the drive
maker's web site.
Let us know.
Tom
MSMVP 1998-2007