Not on any work PC's, mind you. Just systems I build and fix for free, and I use the graphical client, so they can shut it down. I tell them what it is, and so far, it appears everyone's still running it. I don't think any of my buddies would take me to court, but thanks for the concern
OK, performance tips...
When you create a shortcut (always good to put it in your "Startup" folder) to the graphical client or the text-only console, right-click the icon and go to Properties.
In the "Target" field, you should see something like:
"C:\Program Files\Folding@Home\winFAH.exe"
Add the following tags to the end as shown below - be sure to include the space before each hyphen.
"C:\Program Files\Folding@Home\winFAH.exe" -advmethods -forceasm
The " -advmethods" tag signals the server that you have an advanced system and it will make you eligible to receive the Gromacs core work units, which are usually worth a lot more and fold considerably faster than the default Tinker core work units. The boost is very noticable on Pentium4 systems.
The " -forceasm" tag forces your system to use the SSE instruction set for much more efficient folding. I believe without this tag, sometimes the SSE can become disabled.
To run an almost completely invisible client, check out a program called Firedaemon, which allows you to set up F@H (or any other program) as a service under Windows XP (no-go on 9x).