Windows XP Registry Failure during load of mup.sys

So a few days ago I had a problem with my own personal laptop.  This laptop is only a couple of months old.  I had an email with a large attachment (3Mb) that would not go out.  I tried a few things an figured I probably should reboot.  I did my reboot and as Windows XP (Service Pack 2) began to come up I noticed it seemed to take a long time then all the sudden I got the "blue screen of death".  It was terrible.  So I tried a few things, such as restore last known good configuration.  I tried to boot in safe mode which is where I noticed that the last file showing was mup.sys.  I read a number of tech docs that said mup.sys probably has nothing to do with it, if you disabled it then the next file would lock.  GREAT.  So I booted up the CMOS which is the basic configuration telling your computer what features it has and they had a hard drive scan available.  I ran the scan and it failed.  I said, "oh boy that can't be good".  The blue screen message kept going buy pretty quickly and I couldn't seem to pause on the screen so I could read it in detail but basically it told me I had a registry failure it couldn't load the HIVE and something about the System root/system32/config/software being the problem.  So I thought well maybe the drive had a failure on the sector that this file of the registry was in.  BIG BUMMER!  But I stayed patient and kept looking for tech notes.  I found an article on Microsoft's site Article ID: 307545 (formerly Q307545).  I read it and it sounded like it was definitely worth trying.  I'll spare you the details because if you really want to read it you can go find it on their site.  You use the repair capability copy new registry files and copy some more and then again...and the good news is it FIXED the problem.  I followed all the instructions except that of course the SOFTWARE file of the registry was damaged so I couldn't rename it to a .bak file as they suggested.  I skipped that one file but luckily it would delete and I was able to follow all the other instructions just fine.  It is so cool to have my computer back and not have to rebuild the whole thing.  Sometimes if you can afford it, it pays to be patient.