studdering or jittery brushes

[tajhs]

hi, im using photoshop cs 2 and of late my brush strokes are not comming out smooth rather they have a jittery quality to them, as well as when I use the blending tool. Ive trid adjusting several features but to no avail. even replaced my mouse. can someone help me on this.

[Excruciating]

You should check your brush settings in windows>brush.
You've most likely changed spacing or added some kind of size jitter to it.
If it's still not working, reset photoshop under upstart.