remote control software (like teamviewer)

[edscdk]

team viewer would be perfect however its too expensive @ £400 and really by the time i install it on several devices its gonna be £700

It really needs to let a user download and exe run it and it gives them a ID and password (like team viewer) to give me to access their PC

 

[Pho]

You're using it commercially I take it? Is this to connect to external people or internal?

You could possibly use VNC. It looks like it supports listening mode which means you can have the VNC "server" (the user's machine) connect back to your viewer so you aliviate the need for port forwarding at the user's side, just your own. And it's free:

A feature of UltraVNC not found in Radmin is that it may be executed in "Listening" mode, what RPOWER support personnel often refer to as "Reverse" VNC. In listening mode, the VNC server connects outwardly to the VNC client obviating the need for port forwarding through the router at the remote site. (Port forwarding must instead be configured at the local site).
http://rpowerpos.com/pos-wiki/Installing_and_Configuring_VNC

Failing that - http://en.wikipedia.org/wiki/Comparison_of_remote_desktop_software#General_information good luck