Hard drive failure - Compaq N400

Yes, your hard drive may have serious problems. Does the machine have a floppy drive? If so, will it boot to DOS? Or, if you have an XP or linux install CD, will it boot from CD?

Can you hear the hard drive spin up when computer is powered on? Some drives are very quiet, so you might have to put your ear close. Does the drive have an abnormal clicking sound? Western Digital drives were famous for this symptom of failure.

Try swapping the drive into a spare or friend's computer. If the symptoms are nearly identical (no boot), then this points to the drive as failed. Note, that if it does get part way through the boot process, your Operating system (XP, 2000) may blue screen, instead of completely booting. But, if it does get that far, there may be more hope for the drive.

Suggest also you download manufacturer's diagnostic software and run it.

Hard drive failures are very common, some happening within the warranty period or shortly thereafter. This is why backing up your data to CD, flash drive, or other media is so important.