Lacie rugged 1tb ext hd won't show up on desktop?

I am unable to see my lacie 1tb external hard drive on my desktop. I have executed a repair disc (disc permissions wont highlight). I have tried a new lead. I have shut down the system, un plugged everything for 15 mins and rebooted. Tried the usb in different ports. Opened the disk utility for the lacie and I am prompted with a request to reformat?

Everything was workin ok until yesterday. The lacie has many valuable back ups on it. Please help. Many thanks in advance