What is a simple, secure way to encrypt files in Windows?

"I have solved this using Putty Secure Copy, through a Linux box I have on the net. The user downloaded scp to the same directory where the file was, and I have send him the exact scp command by mail.

Kind of reversed the problem - using encrypted connection rather than encrypting the file. Of course, this solution might not fit everyone's needs - it works only if you have a trustworthy server.

But in second thought, one can always install a virtual machine, set the router to port-forward the ports and ask his novice friend to ssh to the virtual machine... But perhaps that's a rather long shot.

UPDATE

winscp works even better. It has simple and nice GUI that every novice user can handle."

"There are two ways for this.

You can compress your file with some archiver like 7-Zip. They can encrypt the content. However, watch out because older versions of WinZIP for example doesn't use strong encryption. In contrast, 7-Zip uses strong AES encryption and can even encrypt file names.

Or you can use EFS. EFS works on NTFS. It doesn't ask you for a password because it uses your Windows credentials. It's important to know that this way you can't securely transfer your files. Your files are only encrypted on your HDD. If you use an USB flash drive or send a file in e-mail than it won't be encrypted."