Windows 7: Free software for prevention of data theft

Hello!

I'm looking for a software which asks for a password when some one tries to copy files from my computer to a pen drive or cd or upload to the internet. In other words I want a data theft protection software.

I know that even if I install such a software there are ways to get around it, but at least it adds a certain level of security. I did a google search and did not find any useful results.

Thanks.

Check whether this fits your bill.

Predator Locks and Unlocks Your PC with a USB Thumb Drive | PREDATOR

There are lot program can do this, like the 7-zip, you can put your files into rar format, it will give your the lock option.
this article introduces Five Best File Encryption Tools, you can pay a visit
Five Best File Encryption Tools

actually windows itself can help you to protect your file or folder by add protect password
Encrypt or decrypt a folder or file

What you're really asking for is read-protection on your filesystem -- which, unless you do full-disk encryption, you're not going to get.

The problem with encrypting folders and/or individual files is that, before you want to use them, you generally have to decrypt them. Somewhat of a pain if you use these files daily.

When you encrypt the whole disk, you have to provide the credentials BEFORE the disk can even be accessed, so, once into the desktop, you don't have to deal with decryption.

If you really want to protect your filesystem against read access, you should consider whole-disk encryption -- but you'll have to move the boot loader files to a non-encrypted partition before you do this.

It should be noted that although full system encryption is eminently sensible, in use the system is unencrypted so any malware encountered might have access to your confidential data. Only unencrypting data as necessary minimises this risk so really it is necessary to do this as well even on a fully encrypted system to be safe. No point in having sensitive data open longer than necessary in my view. Also, although encryption can solve the issue of data theft it often cannot stop data being destroyed so important data has to be kept in additional back-up locations to avoid this possibility.

This functionality is not available on a Home Basic version of Windows.

A better option might be to create an encrypted container and place your user data files within it:
TRUECRYPT - Encrypt Data Folders