When Skyrim was released more than a year ago, it really hated WinXP. It just didn't run it. After half a year I tried Skyrim once again, in hopes that the new patches would optimize the work, but they didn't. Although, there were solution that helped running Skyrim on XP, like adding and changing a few stuff in config. I managed to start the game, but there was another problem. It crashed every time the game saved, so once again, I had to delete it.

A few months passed, a patch came out, and I tried again. The saves were working fine now (along with the tweeks in config that I mentioned above), but a new problem appeared. The game refused to load the data when it was supposed to, meaning, it took from 5 to 30 minutes to load sound, terrain, characters, events etc. For example, you exit a tavern, but everything appears in chunks, without proper rendering, not loaded. No characters or sound, because they're not loaded. You had to either wait for 5-30 minutes, or save/load for the same time. So once again, had to drop it.

Now, some time passed again, patches came out, and here's what I want to ask. People who play on WinXP, and experienced the same or similar problems - are these problems fixed today?

Strange, I've been playing since release on XP and I've never had many problems, and certainly not the critical ones you've described.

Strange. Of course I thought that maybe the problem lies in the hardware, but since I can run Skyrim on high quality with 25-30 fps and since the patches did fix the save problem, I was convinced that it's not the hardware. =/

I hate to tell you this, the core problem is more than likely your hardware/software setup. Have you tried reinstalling XP and see if a fresh slate would help? Have you disabled any services in the services.msc that may be vital?

Haven't tried reinstalling XP, but will have to do that. And yes, I'm sure I haven't disabled any vital services.

Been running Skyrim in XP on my 7+ year old PC for a while now. Apart from the usual bugs that everyone else is reporting I haven't come across anything like you describe.
Try reinstalling your graphics card drivers and DirectX 9 before taking the drastic step of reinstalling the O/S.
Might also be worth performing some Hard drive maintenance like a defrag and varifying your game cache files from within Steam.

While it's possible there is some hardware combination that Skyrim didn't like, and patching has remedied this somewhat, this does seem unlikely. Before you re-install your operating system I'd suggest updating all of your drivers. It may even be worth posting your DXDIAG here for troubleshooting. If you do you should put it inside of spoiler tags, because a DXDIAG report is really long.