I have written some nice software, mainly for my own purposes, that can perform a multitude of tasks. One is the spamming of line of text that you send to the program. When you send the stop command it removes all traces of the spam. It can also simulate deletion, or actually delete, all files of a user (C:\Users\[Username]) very visually, as to shock and panic the receiving user. It can send you the current window title, and a live key press stream. It can also open any webpage of your choice, using Mozilla Firefox.
It does require physical access to the PC, one to disable any warnings by anti-viruses, the other to allow it passed the firewall. It uses uPnP for automatic port forwarding, and if you do not have port forwarding, you need ports 2455 & 2456, sender and receiver respectively. opened.
I can produce a demonstration of it working, say via Skype screen sharing. PM me with any interest, feature suggestions, and possible price offers. I can custom tailor the software to your liking.
Edit: I also have an email based key logger for sale. Far more covert, if total stealth is your game.