Back in the 19th century, Lord Palmerston famously replied to a point about Schleswig-Holstein with the words: “Only three people know about the Schleswig-Holstein question. One is dead. Another went mad. And I’ve forgotten.”

Windows Vista is a bit like the Schleswig-Holstein question.

What is it for? What are/were the objectives? Do we need it? Like Palmerston, I’ve forgotten.

However, I’ve been ruminating a little about Windows Horizon Vista this weekend. And I’ve come to a conclusion which I hope Redmond will listen to. Unless they’ve forgotten what Vista is for too, or lost the will to live.

I believe this could be a perfect opportunity to call the end of Vista. Ray Ozzie’s vision of step updates to Windows rather than the earthquake of a totally new version once or twice a decade is surely the way to go now.

Step updates of a modular Windows — the OS without a name — would be a great relief to many, not least the long-suffering OEMs, who must wonder what strange fantasy world they inhabit.

The nuclear option represented by Vista won’t work if the project is undeliverable. Microsoft should look to Google, with its method of constantly adding bits to a cluster of products. If one doesn’t work, it doesn’t matter. Scrap it and move on. If Vista didn’t work — and it clearly doesn’t yet — disaster.

Even the current rollout of service packs is getting too big for its boot (pun intended). Remember the problems with the 80MB SP2? And SP3 is due this year. Oh, my!

Why not aim at quarterly improvements to parts of the code and maybe a new module or two? So we’d have Windows 2006-Q1, then Q2 …

How would that affect Microsoft’s income? Well, if you depend on blockbusters but can’t deliver, you’re not going to survive for long, however much cash you have in the bank.

So how do you replace a cash cow that’s got too big and doesn’t have much future? The answer is that all cows die eventually, even the best milkers and breeders. Most are withdrawn from service way before they run out of milk.

Windows now needs to be switched from a licensing system, with brand new whizz-bang versions every three, five, seven years, to a system of constant upgrades charged on a subscription model, maybe bolstered by tasteful advertising. Google’s Gmail is a good example of how it could be done.

I know Windows Live is sort of moving in this direction, but I’m more concerned with Vista right now. Admit defeat on that and with SP3 change the name Windows XP to Windows 2006-Q4, and run with that every quarter. Charge us $100 a year for the upgrades, slot in a few easy-on-the-eye ads, and Microsoft has re-made itself for the 21st century.

OK, income will drop, but do what Mini has been saying all along. Slim the whole place down. Redmond is not the Government. It doesn’t need thousands of bureaucrats. Sure, Microsoft will be a smaller company. But at least it will be a better one … and will survive.