Fingers crossed, I think I have removed it. After deleting all the files that seemed to belong to fbdownloader the malware was still hijacking my browser. I did a scan with Spybot which did not find anything, a full scan with Microsoft Security Essentials, which is on permanently, which took 10 hours and that found nothing. I then did a system restore from a week ago and that seems to have cleared it.
I can assure you that at no time did I intentionally install it, no box has come onto the screen asking permission to install it or to change my home page and seems to be a sneaky program that downloads without you knowing it.
I hope that this will help anyone else with this problem, I was quite disappointed with Spybot Search and Destroy as I paid for the Home edition and keep it running in the background and feel that I may have wasted my money.
I use Vista by the way