About 6 months ago, I retired my old XP desktop in favor of a 17" laptop. The old machine is taking up space and needs to go. Before I lug it to the basement, there are some files that need to be erased, lest some unscrupulous recycler attempt to profit from my info. I use WSA to dispose of sensitive files on the new laptop but I don't have that installed on my old box. Short of tearing the hard drive out and drilling holes into it, is there a fairly reliable, easy way to permanently erase the files using (free) software?
Thanks for any suggestions.
The short answer is that WSA can't do this. It's something Window Washer used to be able to do. There is an idea in the Ideas Exchange about bringing back that functionality, and I'd encourage you to add your vote if this is a feature you'd like to see in WSA. To answer the other part of your quesion, yes there are free tools available online that will erase a hard drive. How well do they erase a hard drive? Here comes the long answer...
The long answer is that you might be better off drilling that hole in the disk. If a standard deletion was sufficient to make data unrecoverable, you could just do a format. Most of the time, that would probably be good enough. It's when you start breaking out data recovery tools and running them against a hard drive that you start needing to worry about "how deleted" that deleted data actually is.
Some recovery tools just look at your file table and see if the area specified has been overwritten or not. If it's been fully overwritten already, that's the end of the story. On the other hand, other, better tools can search unallocated clusters. And out of those, the really good ones will have some additional tricks built in to circumvent simple overwriting or partial overwriting.
Speaking out of experience, I once tested a data recovery tool against 30 passes from a free hard disk scrubbing utility to see what it could find. The big files were gone, but a couple of smaller files survived even after they were overwritten with random ones and zeros 30 times. This was a couple of years ago too, but to be fair, the recovery utility I was using was made in 1995 (albeit the best one made during that period), and it stood up pretty well. A FAT32 or NTFS filing system from 10 years ago is still read basiclly the same way today. Out of the files that survived, most of them were corrupt. A few of them still had their original names though, even if the data was gone from them. This can be bad if you have stored valuable information in a file's name itself. Most people wouldn't do something like creating a text file named after their credit card number, but maybe there are file names present that you don't want anyone to know you had, even if they can't see the content of that file.
Another thing to consider is the format of the drive you're working with. Most people are using NTFS these days, but if this is a really old computer and you're still using FAT32 on it, that drive is usually going to be easier to dredge data off of in my own experience. Someone else might have a different experience, but that was mine.
One other thought is that you could encrypt the entire disk and then wipe it out with one of the tools available to wipe disks with random ones and zeros. Then even if a tool managed to dredge up some unrandomized ones and zeros, that data would be utterly unreadable due to the encryption already present.
It realy all depends on how securely you believe this disk needs to be handled. The only 100% secure solution is destroying it, but you can achieve anything between 50% to 99.9% secure depending on how much effort you feel is worth putting into the project.