my laptop is in my exclusive use and control.No juniors around to meddle withit.My wife doesn't know computing.I have a paid version of Norton.I do not suspect any foul play.I do not play games or enter any websites for having a "look".I do extremely docile browsing.I am a senior citizen.I have a software called Wavepad Master's Edition", a sound processing software(paid version) for years now and is using it often.I have the software in C Drive.Whenever I want to record music I use "WavePad Sound Editor".I store the recordings in D Drive.Sometimes I'll have to process the music files from .wav to .MP3.During such times the subject file loads into C Drive from D.After process when i close it, gets back to D Drive by default(by preference).During these times I noticed loss of disk space.There should not be any.The original music file & the processed must go back to D drive and it goes,No doubt.But I notice a loss of up to 100 MB.Sometimes I notice the space recovering slowly.Of late it is not.I use "picasa3".My pic files are in D.Sometimes I load a folder of pics from D to picasa.I find loss of disc space but it should not be as the original files are still stored in D and only a copy is getting loaded in picasa3.These loads shouldn't be reducing disc space.I suspect no foul play from virus,worms or the likes.I must be doing some mistake in my computing.I am a novice to computing.If you are reading it,I have already consumed lots of your time.Thank you.Please guide.