blue screen after administrator logon

> Hello,
> two days ago i got a blue screen, after this i my computer restart and i
> logon.
> I loose my setting like wallpaper, schema, position of desktop icons.
>
> But after another normal reset i can't logon at my administrator account.
> I can only logon as Guest.
> When i try logon as admin i got blue screen 2 second after i write pass
> and click enter.
>
> When im logged as Guest i cant run any program as administrator becouse
> i've got blue screen too.
>
> Number of error is:
> PAGE_FAULT_IN_NONPAGED_AREA
> 0x00000050
>
> What i can do?