A little XP Trouble

I’m running windows xp home edition, a few weeks ago it started acting up and would shut down within 2-3 minutes of being on I would get the blue screen explaining my hardware devices had malfunctioned or something and I figured that I’d have to reinstall windows. But somehow I managed to fix it.

Even though it now runs and allows me to download antiviral programs and such so that I can clean it up it won’t let me access my task manager, change my background from a color to a picture, or access my firewall; even on the administrative account that I’ve repeatedly checked the settings for( just to reassure myself I had admin functions)

Any ideas?