[LAU] [OT] need advice re: Windows registry cleaners (majorly OT)

Greetings, If any of you have experience in this direction, perhaps you could suggest what I should recommend to my better half (Ivy). Her Inspiron is showing the all-too-familiar signs of infestation, slowing down to a crawl and sometimes even stopping completely. She's not ready for Linux yet, so she has to resolve this problem with XP. She's looking at some free and some commercial programs that claim to clean and repair the registry, but neither of us know if there are any especially recommended programs or utilities for such a job. Any advice from the dual-booters out there in LAU land ? Best, dp