Windows has had dabbled in infamy with regard to its security policies. One of the contributing factors to this is that Windows hasn’t followed the principle of least priviledge – to run with as few powers as required, then request further ability when necessary. With Vista, Microsoft has made inroads trying to overlay its User Access Control overtop of the OS, but XP is still entirely out of luck.
That is, XP by default is out of luck. However, there is one program from a Microsoft developer called Drop My Rights that allows you to limit what authority programs have when they are run. The program is in-depth, and allows you to greatly limit the damage if you were to run malicious code.
There’s long been a misconception about the nature of malware and virii, with the lamen user interpreting them as these nebulous dangers that you just “catch” like the flu, not helped by the name virus. A look at the prolificness of the categories of malware show a different story.
The vast majority of infections come from Trojans – programs that users run thinking it’s something else–something safe. While not good to do in any circumstance, the effects are devastating when the program is run with the authority to do absolutely anything it wants on the system without restriction.
In terms of the best protection for your system and containing malicious code, I still recommend Sandboxie, but as a completely free, effective and no risk solution for greater protection, Drop My Rights does the trick.