in reply to the original poster.
XP is full of things that you should be able to do but cannot.
XP is full of spyware.
XP comes with a Microsoft firewall, and do you think that that firewall stops microsoft (or judging by the reliability of their products in the past, anyone) from collecting data from your machine? Of course there are hundreds of undocumented security flaws in windows XP! it is a closed source system which means that flaws will be cropping up for years to come. If it were an open source system, people would read through the code and spot most, if not all, of the flaws very quickly. Those people would probably come up with a fix as well.
answer: No firewall is perfect, no system/browser/program is 100% secure.
The options for someone who has got Windows XP and is worried about security are as follows:
1) live with it, and never find out how many security flaws are in your operating system. Hope that you never fall prey to any security breaches and that you never find out how much of your data is being sold on to third party researchers.
2) refuse to live with it, and get a system that supports permissions, proper encryption, open standards and which has people who actually give a shit about something other than lining their own pockets developing software for it.
Now, a word to the regulars,
i don't think that the original poster in this thread deserves any flames, it is a legitimate question to which i think i have given a legitimate answer. All too often in the past we have seen people posting a legitimate question here and then they get their legitimate anser and then all of a sudden they start foaming at the mouth and spewing insults. This is no reason to tar all newcomers with the same brush. Until and unless they actually do start being offensive and or stupid, i think that it is only courteous to treat them in the same way.
The minute they start foaming though, the gloves are off. Just my two pence..