|"She doesn't use the media players for anything as the PC is used on a network for Dr billings."|
She doesn't have to be actively using WMP 10 or 11 - if media sharing is enabled in either of them , I've seen that there is considerable time the cursor is an hourglass.
"The client is using Avast as the AV."
"The only other program running is Spyware Blaster."
The Avast! version may NOT be just anti-virus.
Look in the program to see what modules it has.
It definitely has at least one resident module. If it has an anti-spyware component, the resident module(s) of that may be clashing with the resident module(s) of Spyware Blaster .
Look in the Spyware Blaster program - is anti-spyware the only thing it does ?
Does it have (a) resident molule(s) ?
I know from experience the current versions of Avast! bog down the computer performance a lot more than older versions did. I recommended un-installing it and installing something else that's not so taxing - e.g. AVG 9.x free or paid.
AVG free has only one resident module - the Resident Shield - that may also apply to the paid version, which has a firewall as well. .
Malwarebytes free is a good backup and has no resident modules. However, it must be Updated after the first time it's installed before you run it.
Notes I made....
How to disable Avast! such as when installing software.
Double click on the icon for Avast! (round blue with a white lower case a) on the desktop.
It runs some tests.
The info/help menu appears - close it.
At top left on the graphical interface click on the up arrow to display the Menu.
Click on Settings.
Click on Troubleshooting.
Click on the blank box beside these to insert a checkmark:
Disable rootkit scan....
Disable raw disk access....
Mandatory - Most important:
Disable avast! self defense mode
(the resident scanner that runs all the time Windows is running.)