I apologise for not responding sooner, but we had a number of public holidays, which lead us all to taking short breaks.
I still do not have an answer, but the following might help.
After talking to my son at length as well as observing what is happening, one can summarise it as follows:
It is not so much of slowing down the desktop, as it is to opening some Windows programmes eg especially my computer, or control panel or devices and printers as well as Windows Explorer.(A perfect example is the second picture in the thread where only a few headings will appear)
After starting the desktop, the above mentioned applications will immediately open fully (first picture in thread), but after a while would just open some key headings. Then you need to restart again.
From personal experience, it does not affect the programmes that I use eg Office, Pinnacle and Photoshop. Currently as far as I am concerned as well as the guy at Major Geeks, the computer is clean.
I am busy running some of the previous scans that hamluis suggested- currently it is CHCKDSK. I struggle with the C drive, as it requests me to restart and nothing happens. The D drive is working cia My Computer.
Some image shots- after starting computer- it was said to ignore system idle.
Again system idle, while Perfect Disk 10 is running.
Look at the "skeleton" screen at the back.
What has bothered me in the past, is that sometimes Perfect Disk would report that 'it appears as if you hace lost a drive' I am just worried that one of my drives is breaking. D drive is quite old (160GB), the C drive is not very old. How do I check the integrity of the drives?
Thanks for any advice