A Pentium 4 or Athlon XP 2700+ from 10 years ago has been unusable for all but the simplest tasks for years. It would have also needed to be upgraded along the way - it came from the factory with just 256MB or 512MB RAM. You can still edit office documents and do some light web-surfing, but for todays interactive sites and content it falls far behind the experience that an iPad can provide.
My mom still has no problem using QuickBooks and doing all the required web stuff at work with a Pentium 4 and 512mb ram. She literally just bought a new desktop because quickbooks requires it.
In an office environment, she really doesn't need more.
