Lost Setting Changes with Dell PowerConnect 5324

Hello All,

I am using a Dell PowerConnect 5324 (24 Port Switch) and I have
connected that to my PC which is running on the Windows XP. I am trying
to make some changes in the settings of the Switch (to be more
particular : Changing the Spanning Tree State from Enable to Disable),
then I hit on the 'Apply these changes' botton at the bottom of the
page; I reboot my system and I find that these changes are not saved.
So each time I reboot my PC and Switch, I don't see the changed
settings saved and its is annoying. Please help.
My PC and the Swtich are connected in the same subnet

Thanks.