Levels and Auto Contrast not working

[asuss]

Hi. First post here..

I have been using levels on line drawings i scan into my laptop and Auto-contrast on images almost daily for years.

suddenly as of less than a month ago, Auto Contrast does nothing for virtually any image i use it on and when i use levels, i can adjust it just the way i want it with the sliding bars, but when i click "ok" i goes back to its original form.

Did i accidentally do something to cause this?

is these something i need to reset or revert back to in order to get the functionality back in both Levels and Auto-Contrast?

Thanks in advance for any help offered.

 

[IamSam]

is these something i need to reset or revert back to in order to get the functionality back in both Levels and Auto-Contrast?

Have you tried resetting Ps preferences?

 

[asuss]

ive done it more than once. doesnt seem to change anything. sometimes when i use/adjust levels and hit ok, it will apply perhaps 50% of the applied changes, but clearly not everything that ive done. ive had it happen a few times over the years and it seems to correct itself after a while. but this is not.