hard drive

There are many reasons:
Cabling issues: If you change a harddrive and fail to set it properly as master/slave or have a defective cable, the bios can't see it.
Bios issues: if your bios has lost it's settings, has improperly identified the harddrive or the harddrive has failed it may not be recognized.

** Older Bioses cannot recognize harddisks above 8mb without special drive overlay programs supplied with the harddrive. Also Windows cannot recognize a harddisk until the bios can see it. If you used a preformance manager which can hide harddrives and have choosen to hidea harddrive it also will no longer be seen.

You didn't give much for us to go on here

regards
rick

Could also be a bad HD.
Does it see it in the BIOS ?

1'Try changing motherboard's slot.
2. " " junper setting.
3. Go to bios enable onboard ide controler both
master & slave.
4. Try to do auto detection ur hdd.Make confirm ur
hdd is well working.

It depends on if this is your system's main HD which has the OS installed on it, or if it is an additional HD you are installing.

1. If this is your main HD which you boot the system with, and you are suddenly having problems detecting the HD, you may need to have the BIOS redetect it. This also may indicate that your HD has 'died'

2. If this is a new HD, you need to make sure that the drive is physically jumpered correctly. Notice that in the BIOS you can have 4 seperate HD setups - 2 Primary and 2 Secondary. Each of these 2 setups have a Master and Slave setting. If you look on the HD it will show you with a diagram how to properly jumper it the way you want it. For example, if this is a second HD, you likely want to jumper it as the Primary Slave - this should then match the setup in the BIOS.

What level of doesn't see it do you mean.

You have to set the master/slave/cs jumpers correctly to have the drive visable in bios.

The jumper settings depend on whether you have another hard drive or cdrom on the cable.

For two drives on a ide cable one has to be jumpered master while the other jumpered as slave, or both have to be jumpered as CS. In CS the position on the cable determines the primary/slave identities.

The last connector on the cable is primary (or master) and the middle connector is the slave position.

Once you have the computer acknowledge the face that it has the drive then you have to partition the drive and format the partition.

Only when you have a designated partition will the computer assign it a drive letter.

Good Luck Lee