Why is it that when I start windows up

it reverts to 640×480 resolution and will not let me change resolution modes back to 1024×768 without restarting the system.
Running a Viper 550 card with 16 mb of ram
Using Windows 98 on Pentium 450.
I tried deleting the drivers and reinstallingthem and it works for a few restarts then reverts back to the problem