Windows XP Home

This past week, as a side project to earn some extra money, I agreed to repair a friends XP HOME Edition Dell PC. IT had about 5 different Serious Issues Going. Since it was a friend I agreed to do it on the cheap. My natural instinct is to Just Scan Data, back it up, and then rebuild the PC from Partition UP. However, I dont consider that to be troubleshooting and my friend had some software on there they would lose. So about 10 hours later, it is working with 95% of the problems gone and the other 5% controlled. I troubleshot the issues individually, as much to refresh and learn as anything else, and learned a lot. My question is what is the point where you check your ego aside and just say it needs to be rebuilt in such a manner previously described versus repairing the current installation? Can you charge just as much for that solution as you would for actually researching and applyign fixes?