Weird thing happening

[nina]

I have a thing that is happening when I play p1999. Often when I am playing there is a pause in the game, sometimes coinciding with a noise as if the disk drive is being used, then a few seconds later the game kicks in again. Its not when I'm just sitting there, but when I'm actively fighting something, or like last night when I leveled. It is enough to make some soloing with my necromancer pretty dicey.
Any advice as to fix this? I'm not running from a DVD rom or anything like that, and it doesnt happen when I am playing on my second laptop (a macbook air)