I bought a Hard Drive

[#1]

Hi have bought a secound hand hard drive but my pc is not seeing it in the my computer but when i turned on the pc a window pop up saying it found new hard where but it will not show in my computer please help me please thank you

[#2]

Assuming you have XP, go into Control Panel->Administrative Tools
Choose "Computer Management"
Choose "Disk Management"
You should see your new drive there.    MAKE SURE you select the correct disk (which should be displayed as 'Unformatted') and right click and select 'Format'
After that, it should appear under 'My Computer' as normal.
B.