So, I started dealing with the situation. Among other things, I used the "Disk Cleanup" utility that came with Windows XP. And compressed all files that hadn't been used recently.
Not to self: don't make system-wide changes after midnight.
Now, I'm wondering if compressing those files was a good idea.
Since I thought someone else might be interested in what I've found on the Web, about this file compression question, here are the better resources I found:
- Ask Leo!: "Should I use Windows File Compression?"
A pretty good discussion of Windows File Compression. (His bottom line: it shouldn't hurt, but it probably won't help much.)
This one may hold the answer to my question. "Martin B" asked: "How do I undo the compression without going to each individual file and reseting its properties?" You'll find the answer at Leo's site - search for "Martin B" .
- the How-to-Geek: "Make Disk Cleanup Compress Older(or Newer) Files on XP"
This post discusses System Restore as a solution.
- Microsoft FAQ: "Frequently Asked Questions Regarding System Restore in Windows XP"
File compression is discussed as part of this FAQ entry.
- Tutor Top: "Hard Drive Cleanup"
More about compressed volumes than files: but a pretty good discussion of compression, with specific how-2.
- WUGNET Windows Users Group Network: "Compress Old Files - What is it?"
This resource says that re-running Disk Cleanup gives users an option to undo what was done.