I had this issue for ages on my old computer. Same resolution- uninstall and delete everything followed by a fresh install. I know that with Sai sometimes I can fix my sensitivity issues with simply minimizing and maximizing the tab but its infuriating none the less.

well this computer is somewhat new so you'd think it wouldnt do it but at least it doesnt want a full uninstall all the darn time

I am always forced to restart my PC to get my tablet working, due to how slow it gets when it boots up at times.

sigh .. gotta love the modern technology

Putting your computer to sleep actually helps CAUSE the issue. Try turning it completely off instead of sleep.
If nothing else, you can go to system, Tablet Pen/Wacom Properties and then stop/restart until it works.
ALSO, if your computer is asleep and you leave Photoshop?Sai/etc open, the tablet will just kill itself. Make sure those programs are fully closed.

ohh prob my main issue then .. i have tried the stop restart thingy but it doesnt seem to help either ..
my tablet does behave better in clip art so im learning to use these days ill remember the sleep part this time XD