Just to update the thread - Steve is now sorted.
His PP2000 is now installed, his copy from the desktop wasn't working and for some reason his laptop didn't read the discs. It read my discs fine so I uninstalled his version and installed and updated mine instead.
The issue Steve was having is with PP2000, when I clicked to open Diagnostics from the main page I was getting an error message, a Mozilla Crash Report. This is because PP2000 wasn't activated, and normally by clicking the Diagnostic menu it would send you to the activation page..

but by pressing F5 ( I think ) the option is there for manual activation instead, which worked.
His laptop was also ridiculously slow to start up, but I think this is because it was searching to open programs that were not on the computer, but by removing them from the start-up menu also seemed to do the trick.
Tried and tested on my 406 last night before dropping his laptop at work to be collected earlier today.
Hint alert..!! If you want your PP/Lexia to stop pestering you for automatic updates when you first open the program, simply use the search feature in Windows, type in PPO.INI and this will lead to a drop down menu. Look for a line that says chrome or something ( can't remember exactly ) and this will lead to a notepad page. Look for a line that says 'Auto update=true and change this to Auto update=false and save the change when you close the window..
This information came from PeugeotForums.