Curved brush strokes coming out as straight brush strokes

[Shariku Onikage]

I recently upgraded my computer to Windows 7 (32 bit) and installed CS5 on it. Everything seems to be fine, but using my wacom intuos 3 tablet i found that when making curved brush strokes every so often it came out as a straight line, the straight line being where i start and finish the curve (see pic below. The S stroke is what should happen. The straight line is what happens every so often with the same motion).



At first i thought it was the tablet and reinstalled the drivers to no effect. Since then i've discovered that the same thing occurs with the mouse. The problem occurs once every five or so strokes (i'm doing digital art, so there's a lot of strokes). It never happens if i do a stroke slowly, but will almost alway happen if i do a fast stroke.

Testing other painting programs i've found them all to be fine (i grabbed trials of openCanvas, Sai and Gimp and had no such issues). However, getting out my old copy of CS2, i found it had the same problem. The problem does appear to be photoshop + my computer based. I've since reinstalled them both but had no success there either. (My computer is a intel i3 btw with 8gb of ram, so i wouldn't believe it to be a performance issue)

Can anyone suggest any fixes?
Thanks in advance.

 

[thedirtyknapkin]

is it possible that you're holding shift?

if not have you tried resetting your photoshop settings?

 

[Shariku Onikage]

The shift thing is a no i'm afraid. My keyboard is away from my tablet and mouse when painting (nor are the shift buttons stiff) and I've not got any shortcuts involving shift on my tablet that i could accidentally lean on.

Hadn't tried the resetting preferences though, so i tried the preset 'Reset all tools' option and then deleted the preferences files is the appData folder for both cs2 and cs5. But no luck for either i'm afraid.

Thanks anyway.

 

[Hoogle]

I would say you have a sticky shift key have you spilt anything on your keyboard recently

 

[Hoogle]

as you load up photoshop straight away press shift+ alt+ control that will reset you whole preference file.

 

[Shariku Onikage]

To test the shift thing i unplugged the keyboard and tried it. No effect, i'm afraid.

Also, cleared preferences using ctrl+alt+shift. The option came up and preferences were deleted. Problem still occurs.

Thanks for the suggestions.