Delay when using right click 'save as' function in all internet browsers

Question

In Windows 10 when using the right click 'save as' function on any internet browser [well,Firefox,Edge and Chrome anyway],there is an annoying delay before it saves the file. I've tried everything that I've seen on lots of forums about this issue,but nothing fixes it except rebooting...then after an hour or so it starts again. Actually several of those options do actually fix it for a short while,but it always starts doing it again after an hour or so,sometimes after 5 minutes.

Some of the things I've tried are:

Disabling every unnecessary service one at a time [disabling a couple of the Intel ones fix it for a short while,same with a couple of other services which I can't remember]

Uninstalled Avast,tried Panda,that fixed it for a couple of hours. Tried 5 or 6 other things,all with the same result basically...the issue always comes back.

Then I actually reinstalled Windows 7 on this machine...perfect for three days,instant 'save as' function again,like it always was on Win 7. Reinstalled Win 10,good for about an hour,then it started again. Is it that the pc is too old for Win 10 or something? [it's 6 years old] Everything else in Win 10 works perfectly on this machine,except this annoying 'save as' problem [only on internet by the way...the connection is fast and reliable,that's not the issue]. It's pretty much unusable like this...it might sound like nothing too drastic,but I need this function to work like it always has before. Thanks