I've recently read that the data that you deleted in windows using shift+del doesn't actually get deleted it is just made to be overwritable by other data that will soon be stored in your hard drive. And just marked as deleted.
And there are some articles like this:
http://www.howtogeek.com/howto/15037/use-an-ubuntu-live-cd-to-securely-wipe-your-pcs-hard-drive/
that shows how to completely wipe out the hard drive of all the data. And thus the data can't be recovered even by the most advanced software for recovering deleted data.
Now my question is, does spyware, virus or other harmful really are lost forever if you reformat your drive?
Best Answer
Yes. Format drive will remove everything including spywares and virus and also your valuable data. Backup your data first before format.
However, there is a sector in Hard Drive that Format would touch. This is the first sector in Hard Drive, the Master Boot Record (MBR). In DOS or Windows 9x time, some smart viruses alter the MBR code and reside in the sector. Even format the drive wouldn't remove the virus completely.
It is advisable you also do rewrite MBR to make sure all malicious code are gone.
To format MBR in DOS/Windows 9x/Windows XP, use
To format MBR in Windows Vista / Windows 7, use bootrec.exe in Windows Recovery Environment:
Read the following article for information on how to start Windows Recovery Environment:
How to use the Bootrec.exe tool in the Windows Recovery Environment to troubleshoot and repair startup issues in Windows