after mac software update - its flicking thur deskto apps andlost trackpad control

hello
I updated the software update (the update I don't know how to tell what was added - but it added the app store icon automatically)

since then
1) MacBook keeps flicking thru the desktop open apps
though I have not touched my keyboard
2) every so often cursor moves by itself and opens finder then creates a new folder
3) lost ability to use trackball
occasionally after I reboot, I get 1 min of trackball usage but that's it

any ideas if it's the software update that did this?
or have I inadvertedly tapped a key to cause this wierd behaviour

thanks in advance

Sounds like you've got a stuck key.

In turn try repeatedly pressing the command/option/tab/shift keys and then see if the behaviour goes away

thankyou - tried that - no change
somedays i get to use for about 15min then it starts....
i use a trackpad not a mouse
ive checked all the keys
ive set all the defaults of trackball and keypad back(under preferences)
ive run sophias virus scanner and nothing found

any other ideas

i have macbook pro
snowleopoard 10.6x