Crashing

jeebus_saves9

<div class="IPBDescription">invalid arguement</div> ok i join a server i start playing and after awhile usually 30 mins or so i start slowing down im not lagging just slowing down like everyone runs faster then me and stuff and it actually happens like others see me going this slow so when i go to exit the game either with escape or with console and typing exit it looks liek it is closing then freezes and a box pops up saying "ns/custom.hp2: invalid arguement and an ok button i hit ok and it is just frozen wont do naythign i have to hit powerbar and turn it off any ideas

1.7ghz dell
geforce 2 mx/mx 400
sound max
256mb ram
windows ME

ns
open GL
1024 x 768