That is the quarantine folder from Combofix. Evidently you did not do a full reformat/reinstall but only a repair install because if you had done the full reformat of the hard drive all files on the hard drive would have been removed. You should be able to delete it by logging onto the computer using the Administrator account. It won't hurt anything by being on there but it isn't needed at all and please do not put combofix back onto the computer. It is a specialized tool to be used in only very specific conditions.