Inspiron 1545 - F8 restore factory settings not working

Hi,

I have an Inspiron 1545 laptop that I bought in November last year. I restored the factory settings a while ago to solve an issue and would like to do it again but when I try the F8 on the boot menu and choose repair my computer option it goes straight to the normal log-in and I don't get the option to restore.

Is there another way I can restore my laptop to the state it was in when I got it? Any ideas greatly appreciated!