My PC is cranking down again

Two weeks ago was last straw. My PC was just cranking down that it was painful to do anything. I would doubleclick on something and it would just sit there. I would wonder if I actually did click on something or maybe I just mis-clicked. It was super frustrating.
And every year, it’s the same thing.
On average, I buy a new PC about every 2 years. Part of that reason is because something new and faster is out, but sometimes it’s simply because my PC has gotten loaded with so much crap that it just eventually takes Windows to a crawl.
At times, I can fix it by deinstalling stuff. Other times, there doesn’t seem to be anything I can do from a program installation standpoint. I’ve removed everything I can that I don’t need and still it won’t speed up. Performance on what was advertised to be a fast PC grinds to a halt.
Why does this happen anyways? Is Windows just so screwed up that it can’t handle a graceful evolution of a user who accumulates more data and software over time? Certainly Windows is just too complex for any normal person to fix. At one time, I could have administered my PC and Windows. But not now. It’s changed so much and you can spend days looking up books, stuff on webpages, and trying various things to see if they will actually work.
It’s a huge waste of time. Perhaps on par with the productivity hit of having a super slow PC.
So I have to buy a new PC. Instead of trying to figure out what I can do with my current system, I opt to pay a few thousand dollars and just buy a new machine. Isn’t that ridiculous? The other option I have is to dig up my restore CDs and just wipe my system. But then I’d have to know how to back up all my data and programs, and assuming that I didn’t forget to copy something, then spend hours, if not days, reinstalling every program that I have. I just don’t have time for it.
This time I got a little lucky. First I bought Diskeeper 10 and it seems to work pretty good at defrag-ing my hard drives. That helped, but system response was sluggish.
Then I bought 512MB RAM, which was a slight adventure in figuring out exactly what module was needed for a 2 year old machine. Amazing how these standards have changed in only 2 years as new PC models have been introduced.
I install that and it seems that system response is zippier. But it wasn’t back to the way it was when I bought the machine.
I keep thinking about this. Why is it such a pain in the neck to keep my Windows PC running at full speed? UNIX doesn’t seem to have this problem, or the Mac. Instead, most of the time I resort to buying a completely new machine instead of going through wasted time and frustration of trying to figure out exactly what was cranking down my machine now.
It just doesn’t seem right. But for now, my machine seems to be running a little better. It makes one think about money versus time spent or wasted versus the growing complexity of software for PCs. I long for a time when my PC will run reliably and speedily as other electronic devices, like my XBOX or mobile phone.