I have about 30 of these files which I think are potential viruses

Nope thumbs.db is a perfectly legit file used by windows for image thumbnails.
What anti-virus are you using and have you updated and conducted a deep scan ?

Thumbs.db yes these I know are OK. The ones I have are thumbs.db.vir
I use Microsoft security essentials and Sophos vrus scanner

Are you using any cloud services?

Not intentionally