wrote:

So only soultion is to buy new mouse....??? Logitech Mx518???

No! Follow these steps:

· Try a black mouse-pad [u dont need to buy1, u can find smth like it in your houce/office]

· Make sure that the optical sensor is clean!

· If it has ps2 interface check the refresh rate, and increase it [http://www.majorgeeks.com/download299.html]
If usb try [http://www.geekstogo.com/forum/Tweak_Your_Mouse-t19890.html]

· Change Windows mouse settings - enhance mouse precision, speed etc. Also increase buffer size!

· If you have SP2 installed it may couse this kinda problem too -Im not sure, a friend of mine told me he had experienced that.

· Uniinstall the software provided by the vendor (Logitech)