I've never had problems with it until now, so I thought I'd go here before going to customer support.
I've had this Razer Deathadder for a few months now, and I haven't had any problems up until a few days ago. I reinstalled my steam to fix a few game issues, and when I reinstalled L4D1, my mouse was acting weird (this is only in l4d1, I guess, although it isn't perfect in other games). Whenever I move the mouse across the pad, it starts to trail off a little bit on my screen. It's nearly impossible to aim if I need to turn at all.
Since this happened, I've reinstalled both steam and L4D, and checked my mouse settings, my mousepad, and all that stuff. I tried a different mousepad, but it only seemed to get worse (I have a Goliathus Control, btw)
If your mouse is plugged into a USB slot then you may try changing to different slot(s).. Also try changing the in game settings for mouse sensuiuity.. If you've any drivers installed related to your mouse then just uninstall them..