is there anyway to completely clean a hard drive where no technology could pull up information from the past from that hard drive?

Lol! The first (electro shock tx) sounds do-able!  Trouble is, I don't really want to lose everything, but am most interested in clearing some emails and some documents.... What are you doing up at this hour? 

You can use Spybot Search and Destroy. It has a function that deletes old files, overwrites them with gibberish then deletes the gibberish. You can even specify how many times you want it to overwrite.

Another way to do it is to transfer the files you want to keep to a new hard drive then format the old one.

LOl --when i first read lab tech to draw blood my mind was thinking "yeah, computer techs do draw blood!" then I realized what you were saying...hope the tests turn out good!
Sid, thank you--I will check into Spybot search and destroy...I knew that old info could come off of old computers and wanted to clean this one...it's an old Dell but not going to get rid of it yet...I had put it "up" and used a new one for a while that Glen had built, and it did ok but lacked some amenities that Perry had built into this old Dell...when the "new'one contracted some viruses and started crashing I just put it up and dug out this old Dell...my computer technology skills consist of "click" and read unfortunately, but my grandkids are pretty savvy so will probably enlist their aid with the spybot thing....Thanks!  It's pretty serious that I get this done just in case...

And then I come in and un-format the drive with a recovery program....
Writing zeros to the drive seems to be the best way to wipe a HDD clean.
http://www.dban.org/
or
http://killdisk.com/downloadfree.htm

May not be necessary to clean it after all, but if i do, I will keep it in mind...about the zeroing...in the old days, one just got rid of the typewriter ribbon...

In the new days one opens up the little sucker and uses the magnets for some funky stuff. The platter looks pretty cool too.

the magnets can be epoxied to the brake disc of your motorcycle, to close a magnetic switch on the front fork with every revolution of the wheel. Thus you turn a $20 bicycle computer into a motorcycle digital speedometer, instead of spending $500 on a new BMW instrument cluster. But you need the powerful rare earth magnet from the hard drive to make it work at motorcycle speeds.

See what I mean? There's a funky use for a powerful magnet.