Hey ive been trying to get counter-strike, team fortress, half life ect ect to work but the game always hangs after a few minutes of playing, anyone got any ideas how to fix this??

ok my puter is
Pentium 2 450
windows 98
128mb ram
directx 9
Quantum3d raven/voodoo banshee graphics card

Ive tried loads of 3rd party drivers and ive ended up having to format my puter so many times im going to scream if it screws up again, any help would be greatly appreciated