This is a basic "drop in" process. Drop in your new fah client, and move your old fah client, out of the folder. (don't delete it just yet).
You may need to unzip the new client file, but there will be no need to run install again.
Finally, you'll name the new fah client, the same name as the old fah client. (It won't care, it knows what version it is).
Your service settings won't know the difference.
Delete the client.cfg file to force the client into config mode. The fields in the client.cfg file have changed.
Ok, download the executable drop in 6.29 client, from here:
http://folding.stanford.edu/English/DownloadWinOther
The file you want is the "drop in binary", don't get the one's up above it!
More upgrade info in detail:
1. Stop the current client by using Control Panel >> Administrative Tools >> Services. Highlight FAH and right click (or select "Action") and choose Stop.
2. Open your current folder (that you used to run the smp client).
3. Either rename or delete the old Fah executable.
4. Unzip/copy the new 6.29 executable in the same folder.
5. run the new executable with the -configonly flag then check the config (there are some new fields to add).
6. Restart the client as usual.
Do this after a WU is done, or just starting up. It's not unusual to lose a WU when you upgrade.
Rock On!