Drive not recognized
 

As a newbe to linux I have been trying to get my head round it's workings and am using an old HP machine. I have linux installed but when I boot up the HD is not recognized but if I press cnt/alt/del it will boot and run normally. Is there a way to fix this problem?
I have looked at other sections but the answers are beyond me.

Hi,

A little more information would help!
Your distribution, kernel in use and hardware specifications would help.

FYI: I suggest that you look at 'How to Ask Questions the Smart Way' so in the future your queries provide information that will aid us in diagnosis of the problem or query. That way you will receive targeted responses.

Thanks, Gary, for your suggestions.
I am using ubuntu which has been updated to the latest edition which works well. The HD is a 20gb drive on which I installed ubuntu about one year ago but had not used for some time There is 512mb RAM installed.
The strange thing is that neither the bios nor ubuntu recognise the HD but do find a 4 gb usb stick.
I can live with this but was just wondered why this happening.

Means you are running ubuntu from the usb-stick or live cd ?

BIOS doesnot recognize the HDD, means there must be some issue with hardware.

Disconnect and reconnect the HDD cables and try again.