I would open task manager (ctrl+alt+del), open the menu in the upper right and hit New Task.
Type in "cmd" and if it asks for administrator privileges , say yes.
Once the black window thing pops up, type in "sfc /scannow" and hit enter. Then wait. This will look for damaged system files and such.
My family PC had (probably, assuming I understood your post right) the same issue.
I hope I made sense.