MS made up this so called "Universal Plug and Play." The instant I read about it, I knew it was a bad idea. Network devices shouldn't be searched and automatically configued.
MS made it up. They enabled it by default on their operating systems... you know the story.. we are MS, we have a desktop monopoly, we will bundle something with the OS and force it on customers and then all the businesses will pick it up.
It was a known security risk.
It was known to cause problems.
My work computer runs XP pro (I don't have a choice, it's the company computer, they own it, company policy says I don't put any other OS on it). For months after I put on SP2 (again, I didn't have a choice), the damned thing would just slow to a freaking crawl for no reason, because the WINLOGON.EXE program would go haywire, and the only thing I could do was reboot it. GRR.
I made sure I had no malware. Finally I find out that this happens sometimes when you have UPnP enabled, and SP2 re-enables it by default. WTF.