Out of Disk Space Due to Adobe Reader?

Problem:
A client asked me to investigate why his old Dell Windows XP computer was so slow, and mentioned that his hard drive was almost out of space. Indeed, only about 2 GB were left on his 80 GB drive. I figured that it would be a straightforward hard drive upgrade, or indeed a replacement of his old tower with something new, until I checked around. I quickly established that his user profile contained over 45 gigs, but then found that his Documents folder (the usual culprit) only had about 3 GB. Application data? About 42 GB. Hmm.

Solution:
I quickly narrowed it down to the Adobe folder. Inside was a folder called plugs, and inside that were two 20+ GB files, apparently the fruit of some repeating update process or another. I found that he was still using version 6 of Adobe Reader. I deleted the files, updated Adobe, and removed a startup entry that seemed related to Adobe updates. Now we'll see if the problem reoccurs...