Windows NT Workstation Locks Up

I am running windows nt workstation on a windows nt network. I have office 2000 loaded and sr1 patch installed. The hard drive is a ibm 26 gig with an ultra 66 controler card. The problems is the computer locks up when running office and exchange e-mail programs. I get lines going up and down the screen and the only why to restart the computer is to push the reset button. Any help will be great! Thanks and have a good day!
Ernie Harper