Vista - Control panel no longer opening / No access to Security-Updating

Just booted my pc this morning to find I cannot:

1. use Windows update update via start bar, I have to get updates via My
computer and use update from there.

2. open Control panel via any given icon, the control panel window opens and
then closes automatically.

3. No longer have access to firewall / update settings in Windows Security
Center.

It's as if it's back to the stage when I got my pc last week, as I didn't
register Vista straight away and didn't get that access too the above until I
had.