HELP - External Hard Drive Saying To Format

I've been using an external on my laptop for the last month. It has been working
good until now. Last night, I safely removed it and turned it off, then put the computer in standby. When I turned the computer on this morning and then the HD, double clicking on it said it needed to be formatted. Usually I don't do the safely remove part because it sometimes would say it couldn't stop the HD so I would just put the computer in standby, then turn the HD off.
Is there anything I can do to get a computer to read the files on the HD. I hooked the HD up to my desktop and the same thing happened.
Are there any programs I can buy to revive the files on it?
Any help would be greatly appreciated. Thanks!