Question Author
Thanks SlackAlice. Really helpful answer.
I am using a HP Printer, but just to be on the safe side, followed the link to remove the HP aspect from Start-Up. Did the trick. I can reload the drivers via your other link as start afresh.
Your advice regarding Norton Firewall and Skype was spot on. Everything listed said "Allow" except Skype, which said "Blocked". I changed this to "Allow" and it now works fine.
All is now well except one final thing. Whilst the "TrayApp message at Start Up has gone, the one saying "Windows Installer is configuring Destinations" and needs the Destinations disk etc is appearing. This may still be related to HP but not sure. I did a Google search and found something about doing a "Clean Boot" but was unsure how to do this properly, or if it will help/cause other issues. Any advice appreciated from any ABer.
Many thanks