I never said it did. What I said was that Firefox became unstable on my machine and when I stopped using it my problems stopped. Coincidence? I don't believe in coincidences.
I never reinstalled XP. Never did anything except to change browsers and the problems stopped. And don't even start me on Thunderbird. That thing got so screwed up that it virtually brought everything to a standstill.
I'm not here to defend Microsoft. I'm just relating my own personal experience. Make of it what you will.
I'm also not arguing that the hard drive on his machine might not be faulty. But before I would go that route I would try other things. My wife's machine was supposedly in need of a new hard drive but when I reinstalled the operating system the problems went away. Strangely enough her machine is still using Firefox and Thunderbird.
This is really hard to believe but it is true. At some point in time about 16 copies of the operating system were installed on her hard drive during a thunderstorm. I couldn't figure that deal out but it took forever to boot up. I tried the usual utility programs but nothing worked. However, reformatting and reinstalling the operating system fixed the problem and that was over a year ago. The hardest part was finding and reinstalling all of the drivers. That hard drive I was told was faulty still soldiers on although I was informed by "experts" that the hard drive was most certainly fried.