Actually looking for something else using Google, I stumbled on a good page about disabling services in Windows XP. This makes more memory available, a thing I really can use with only 128MB.
Also a thread on Google PageRank in the Usenet group alt.www.webmaster made me finally use the mod_rewrite module on my sites to remove the www prefix. Versions with and without the www are used to link to my sites, and I am afraid this is bad for my PageRank in Google. Others confirmed this is the case.