Unless of course, you happen to be a victim of this (or numerous other similar) bug:
How to recover from a corrupted registry that prevents Windows XP from starting
This problem has been in existance since Windows 2000 and there is NO fix available.
This happens about every third or fourth boot on my home PC. MS, whose support was very timely!!, sent me a "hot fix", but nogo - SP2 (already installed) already contained the fix, but the problem occurs anyway.....
So, while I will agree that XP is far more user friendly than both it's predecessors/most of the competition, it is only so when everything works. When a problem occurs, the user is generally "SOL".
That's too bad you somehow contracted that problem, but it is quite rare, at least in my experience. I provide oversight of a network consisting of thousands of XP clients and I've only heard of that problem once before. You're of course welcome to load some other operating system, but I'd either reload Windows from scratch or buy a Mac. Switching to Linux is certainly not going to make anything easier, keep in mind the only way the Linux companies can make a profit is by charging for service, so it's certainly in their interest that you will need it.