Firewall Enable

My apologies if there is a posted fix to this problem. If someone can point me there (if I ever find my way back to this location!), I am more than happy to read it.

In brief, we have a 2002 Dell Inspiron, Windows XP Home (2002 version, I assume, since it came with the computer). We also have BitDefender InterNet Secutiry 2008. Four family members, four "accounts," four users.

For the last two days, my wife's "account" has two "critical" problems, one of which is that the firewall is not enabled. I forget what the other one is, but we can't fix it, either. Every attept to enable the firewall, using the on-screen icons, results in, well, nothing happening. No wizard appears to lead us through the necessary steps, and not change in status occurs, either.

Any suggestions?

Thanks.

Dan