email encryption for Eudora

Can anyone recommend a good email encryption program for Eudora 5.1 running on Windows XP?

I read about PGP encryption but found only horror stories in ratings at ZD net and one other download site. Apparently, PGP does NOT work with XP. Many reviews cited the BSOD and no way to recover except in Safe mode.

I need something fairly professional for a single user working with Eudora.

Thanks for any help with this.