Win98 freeze’s

I have a 700MHZ PC with 256MB of RAM. At lease 3 times a day the PC freeze’s- My User and System Resources range between 32% to 50% and my GDI resources are around 84%. My available phyiscal memory ranges from 130MB to 180MB’s. I have the following utilities activated: NAV 2000, Zone Alarm, and MEM Turbo. Today I just did a print screen capture from within Eudora 5.0 to Word 2000- when I tried to print the Word document my pc froze and I had to do a hard reboot.