Placement of shortcuts on desktop

Hi,
Has anyone else encounted this minor irritation, and if so, is there an answer.
I have many shortcuts displayed on my desktop and they are all spread around the desktop and strategically placed around the main image on my desktop so that none actually sit over the image. They are also placed together in related groups.
For years my PC always opened up with the shortcuts situated where I had placed them on the desktop. However, in the last month i have twice turned my PC on to find all the shortcuts bunched together on the left hand side of the screen, and had to waste time putting them all back into their correct positions.
Has anyone an aswer to this?
Thanks,
Barry

Thanks for the suggestion Bill1. I run Malwarebytes Premium, which I have a lot of faith in, and I just ran an extra scan to check, which found no problems.
Barry

Thanks again Bill1. I've changed my resolution from 1600 x 900 to the recommended 1920 x 1080 and will just have to wait and see whether that sorts it out.
Barry