First step, Check the CMOS battery; size of 5 pence on the motherboard-if a few years old ,turn off power ,replace it with a 3V lithium new one! Restart- press Delete to Enter BIOS and reset the date+time if connected to internet ,Enter Control Panel ,Click "Time and Date" afetr adjusting date/time Syncronize "time.windows.com".Go to dell.com + Update ,run Dell Diagnostic Tests for your Inspiron 1545.Hope this helps