My 4 1/2-year-old Vista computer is really acting slugging lately, even giving me seemingly random "Not Responding" errors way more than I like. I run DEFRAG often, have done a Windows Disk Cleanup, and a couple of other things that haven't helped. I'm wondering if some registry-cleaning software like PC TUNEUP might help here. I guess I've heard some good things about such tools, and some bad things. I know if I upgrade from ZASS to ZA Extreme Security for $10 I would get this utility included.

Can anyone offer any advice about this? Have people found that running PC TUNE-UP really helps? Is it worth it?