Most later model logitech mice are great for gaming, I use one myself and have had no issues with it.
First check the table is flat and not sloping a bit. Laser mouse should be way more accurate than an optical.
Next make sure if also using a touthpad, etc, it's not interfering - if so disabled it.
Changing PS/2 port might solve your problem, USB connection is much better to use.
It could be your purchased mouse is faulty, if still under warranty you should be able to get it replaced for free.
I would also suggest going wired for any mouse, it's annoying for gamers due to long hours playing + batteries = instant death and also interference from other electrical devices such as your sound system, monitor, etc. Also don't use a wireless for the net when online gaming, lag and more interference!
I use the Razer mousepads, it's a large surface smooth area and the texture on those makes the mouse high accuracy - great for hardcore first person shooter games.