If the computer was designed and released with Windows ME, then you're dealing with an up to 10 year old computer. This is ANCIENT in regards to computers considering the advancements in software and applications which need a much more powerful system to execute in a timely manner than 10 years ago.
One thing you can check is the RAM. Windows XP Pro is recommended to have at least 128 MB RAM. If your computer only has 64MB it will run, but it can really slow it down, below 64 and it's going to be nearly unusable with Xp Pro. Ultimately, if you're trying to run XP Pro with office applications and other features on a basic computer that's 10 years old, expect it to be slow especially launching the applications.
