Oops! I just realized I did not clear the TEXTAREA field where I had begun writing before posting :-[.

sloat, all versions of Microsoft Windows operating systems (with the exclusion of 3.1 and possibly 95's edition) allow for the performance to be tweaked and enhanced through several different methods, and believe me they do indeed help. Generally when I make a clean install, or try to optimize another individual's computer without getting too involved with the hardware aspects, I run "Hijack This" to enumerate all of the Browser Helper Objects, Toolbars, ActiveX files, applications running on startup, remove all of the unnecessary clutter, and then move to the services configuration. By default there are a lot of resource-wasting applications running in the background, and so I look through each service and then set ones I may possibly need to "manual" while disabling others completely. This is a great way to free up RAM, and minimize certain plugins' impacts on the computer.
Next I deal with visual effects, both "documented" and "undocumented". I remove all of the quick-launch icons from the toolbar as apparently those have a small effect (or so I have read, but I don't use them anyhow), enable the classic menus, set the theme to "Windows Classic", adjust the system properties' "Performance" settings so that there are no forms of animation, and then set the swap/page file to 3 times the amount of RAM actually contained within the computer. After this I run an additional utility to modify other aspects that aren't easily found such as:

sloat, every single edition of the Windows operating system created by Microsoft (possibly with the exclusion of 3.1) allow for the performance of general applications to be greatly increased through various tweaks and enhancement methods, which do indeed help tremendously, and also positively impact the overall reliability, stability, and usability of the system without addressing any additional hardware issues. Whenever I freshly install Windows on my own computers, or on older computers owned by other individuals, the first thing I do is execute "Hijack This", which allows one to quickly scan a number of sections in the registry in order to enumerate all Browser Helper Objects, toolbars, ActiveX files (included in the browser), software that runs at startup, and many other areas where both legitimate and malware files are known to create issues. I remove all unnecessary clutter keeping only what is required to properly maintain Windows along with a few select applications. Next I tackle the services (services.msc), because by default there are quite a lot of resource-intensive, and resource-wasting tasks operating in the background, and so I go through each one setting flexible important ones to "Manual" while disabling others in their entirety (such as "Tablet PC" when most desktops and laptops do not include these features). These are a simple yet great way to free up RAM, and minimize certain plugins' footprints or impacts on the computer.
Proceeding along I deal with the visual effects and aspects of the operating system, both easily accessible, and "undocumented". I have read that quick-launch buttons on the taskbar do use a lot more memory than one would think, but being as how I do not use them anyway I opt to remove them before setting the taskbar panel to appear as the "classic" one did, and disable highlighting of newer programs. I then set the theme to "Windows Classic" (goodbye rounded-windows), and adjust the system properties' "Performance" settings under the advanced tab so that the system is modified for best performance (no window animations or other effects). Then I run an additional utility to address the menus' delay time, look, and a few other options effecting everything from how the text appears to Internet Explorer's maximum simultaneous connections, or the number of half-open sockets. After this I modify the swap/page file to a customized setting which is about three times greater than the total amount of RAM I have. There are literally hundreds of other ways to enhance the speed of the system as well such as setting the graphics card for performance, disabling the file indexing option (this allocates more RAM for free use, but takes longer to search for files), disabling superfetch, or even the compatibility engine used in Vista. All other portions of the computer such as specific software can also be configured for performance. Like I said, it doesn't take very long to do all of these, and although I have not updated the Windows Experience Index on my laptop it is currently a 3.1. The ratings are out of 10 I believe, and your score can never be greater than the lowest value which you have attained.
As for the CAPTCHA I find it to be interesting, because instead of a combination of characters which can easily be recognized by OCR technology, and instead of compromising your usability by making it overly difficult in order to fight the character recognition issue you have instead created a simple way to prove that a poster is a human as opposed to a bot. I cannot remember off-hand what the last question I received was, but I believe it was to choose a real word out of a few groups of characters. This one is a "True or False" scenario, which again is easy to use. I'm not an expert on CAPTCHA methods, but I'm going to present your CAPTCHA on sla.ckers and see what they think of it in terms of overall effectiveness.

I am more of a Windows person myself (colliqually referred to as a Windowsfag), but that is mainly due to the fact that it has always supported everything I have ever wanted to do. I do however run VMWare on ocassion using FreeBSD/PCBSD, BackTrack 2, and Windows 98SE (I use it as a development environment). I have never had any issues with Vista as far as performance goes, but I have thoroughly cleaned the registry, removed all unnecessary BHOs and ActiveX toolbars, disabled all unneeded services, deleted many of the programs wishing to run on startup, set every setting on the graphics card and operating system to "Performance", regularly defragment my drives, and replaced much of the utilities with light-weight alternatives. All in all it's about a half-hour worth of work, but it's decent. By the way is this a custom CAPTCHA, or is it available somewhere on the internet?

I used to have a dual boot of Windows XP and Ubuntu. I found Ubuntu to be pretty slick. Sorry to here you had such a bad experience with Kubuntu.