not always the case Windows XP will run on a system with 64 mb of memory but will hammer the hard disk as it has to do vast amount of paging data to the hard disk.

Not to mention once you have replaced those valuable important documents/files you may end up in exactly the same situation, what if one of these documents has a scripted virus.. word and excel viruses are widespread.

Things happen for a reason you simply have to find out why.