Monsy, I had a short ponder then decided to find out more. Thanks for the screenshot and yes! That is exactly the site from which I downloaded and undertook the scanning. The Glary Utilities Scan and results develop into an order form and eventually a price, and by then the company receiving the order is called Uniblue. You might say I've been caught but I found the item had been reduced from £39 + VAT down to £19 +VAT.
So, having received a small unexpected windfall of £20 at the w/e, I went ahead, and it is on its way. Maybe unwise but not a massive amount.
I appreciate your being wary for me. Had a phone chat with the man who fixed the modem problem and he said everybody probably has faults in the registry and some become corruptions, and the fact mine was called 'danger level' with 521, was not so panic-making as I feared.
Viv