they haven't fixed crap...
bandaids on an artery come to mind...
Microsoft is doing everything they can to make their software more secure, but if there weren't so many criminals targeting Windows it wouldn't be such a problem. If Apple or Unix were the dominant platform, I guarantee you would see the same level of hacks on those platforms.
Your best bet is to use anti-spy and anti-virus software and enable Windows automatic update feature or visit the Windows Update web site every once in a while. If you do that you'll be fine. That's what I do with the 4 PCs I own, and they all have no problems.