Ok well the attached link goes to the lenovo support and download site
http://www-307.ibm.com/pc/support/site.wss/homeLenovo.do?country=uk , which is a model of it's kind. I see that no Lenovo model was issued with a drive larger than 250Gb, and it could be you need a bios (flash) upgrade to support the new drive. On the whole I think not. You should instead look in the bios and determine if the order of hard drives is correct - this is entirely different to the boot order. in brief, you need to first choose the drive
channel that is looked at first, then determine the boot order on that channel.
Either way, a drive C: will only appear when you have your new drive as the first non-removeable drive. It would appear to me that you did not follow a viable process for getting things going on the new drive. If you actually want to migrate everything from an old drive, the best method is to use 'drive image' software (which is available for not a lot e.g. Acronis true Image, or even free alternatives). You image your existing drive to removable or preferably attached USB media, either as one large file or a number of smaller ones to match the media in use. There is also a way to boot from a CD or floppy disk with a new empty hard drive replacing the old. Finally, you 'restore' the drive image onto the new drive and away you go as if nothing had happened.
You can either restore the new drive at the original size, and add an extra D: partition to use the rest of the space, or you can restore it filled out to the full drive capacity. I cannot go into the pros and cons of each approach here, suffice to say if you want to image a complete drive to protect yourself against a catastrophic infection, where do you put it? Answer - on another partition.....
Some hard drives even come with a chopped-down version of imaging software to do exactly this, and no more - you just install a package on your existing drive, plug in the new drive and run the software which simply copies the whole hard drive onto the new one. Swap in the new drive and you are done. All in 15-20 minutes....Seagate comes to mind. Check their website.
As to where you are now, why the new drive will not format etc, I recommend you download the FREE partition manager from here
http://www.easeus.com/download.htm which will show you all the drives, their letters under the existing setup. I think you probably need to clear everything off the 500Gb drive (with say FDISK or Easeup itself) and start again.