Can a virus corrupt a hard disk?

This Dell technician is partly right. In the past, there were viruses which could damage a hard disk. They did this my moving the read-head of the drive to a sector outside the existing range, causing the head to bump against the internal frame of the drive itself, causing damage to the disk. But that was almost 25 to 30 years ago and hard disks have become more robust ever since.

Now, it is possible that something went wrong inside the BIOS settings of this laptop, thus the BIOS won't recognize the hard disk anymore, or just can't access it. This could be some virus trying to damage the firmware or just a user messing with the wrong settings. Restoring the proper BIOS settings should fix it, although you would need to know those settings first.

Finally, if you have warranty on the hardware then it doesn't exactly matter how it got damaged beyond repair. It is broken so they have to fix it. (Although you might want to check the warranty papers that you received with your purchase for exact details.) Do make it clear that you demand a replacement for this disk, which falls under the warranty. (Else, be prepared to ask for legal advise!)

I myself have a Dell desktop. I know they install their OS from a special disk image instead of doing an official setup. A regular setup would just format the disk, mark bad sectors and do a bunch of other stuff to make sure the disk is okay. Restoring a disk image won't do such checks but just does a quick format before putting the image back. If this fails for whatever reason, oops...

It's impossible, nasty viruses can erase the MBR, but a format can fix it. Try to wipe the disk and install it again (assuming that Dell, unlike HP and Lenovo, was rich enough to give a $0.40 Recovery DVD with a $1000 computer)

But, poorly made recovery cds will hang if the partition table is different from the original one. Did you do some changes to the disk layout?

I think you are misunderstanding what the technicion is saying. If someone says a drive is corrupt that refers to the data on the drive, not the hardware. Corruption may be caused by physical damage or non physical such as a powercut or virus. If there is no physical damage then you don't need a replacement drive, you just need to reformat it.

You can't 'repair' because the partition is corrupted so this needs to be deleted by reformatting and then you need to reinstall windows. The Dell install disk gives you this option. If you see an existing partition on the drive delete it and recreate a new one for the install.

If you have data on the drive that you need to keep, you may be able to recover it by attaching it to another machine. If you don't know what you are doing take it to a professional (although this may well be expensive) without trying yourself because it is easy to render the data unrecoverable.

Back in the bad old days when voice coil drives were new, there was a virus that would physically damage some particular hard drives. Doing a request to a cylinder greater than was available (repeatedly) would get the heads to do a reset cycle, followed by running out the number of cylinders/steps requested. That would be greater than the allowable travel, so the heads would crash against the stop, that would be detected, it would reset, retry... Eventually some hard drives would fail from that treatement. Way back in the 286/386 era they added better brains to the drives and that particular method of using software to damage hardware has disappeared.