Now you have it working on the Last Known Good there is ONLY one course of action suitable in the circumstances.. I cannot advise you further as on this site to ensure you receive the bext advice, ONLY certfiied Malware experts can deal with these issues.
Please go to this link follow carefully the advice in the link and post in the Malware forum to ensure that you then receive a clean bill of health from an expert.
Include in your post a link to this thread HERE please, so that the expert can see what occurred.
If when they have ensured your computer is then NOT infected any longer, you can post back here if they so advise, should there be any remaining issues.
My advice is DO NOT run the scan again yourself.
You may not recover on a second occasion.
Good luck with it and pleased to have helped in some small way.
but do I still need to try and repair Windows XP or would it be fine?
You cannot rely on a repair install, to ensure you are clean.