Question My pc is being really slow and idk why?

[BsbSlayer]

Whenever I boot it up it’s fine and everything is good but, a couple seconds later the screen flashes black for a second ain’t then the toolbar turns a see through white and I can’t click or do anything without it taking 100years. I think it’s a gpu issue but does anyone else have this issue?

 

[TheFlamingCharizard]

Is this a problem that just recently came up, or had this been happening for awhile? Also what are you computer specs?