Drive Wiper

I am giving my desktop to a friend. Is drive wiper a secure way to clear my hard drive? Will it wipe the OS?

Yes it is designed to clear your drives and make the deleted files unrecoverable.

It will not let you completely wipe the OS drive for obvious reasons but will clear all but the OS.

More info here:

https://www.ccleaner.com/docs/ccleaner/using-ccleaner/wiping-free-disk-space