Hi jcball and welcome to G2G!
The first thing I would try is a system restore to a previous date when Windows XP was working OK.
Click start > goto programs > goto accessories > goto system tools and click system restore > once system restore opens > click restore my computer to an earlier time > click next > select a restore point when Windows was working on the calendar and then click next. It will start doing the system restore and will reboot your machine as part of the process. The system restore process can take up to 15 minutes depending on your machines specifications.
System restore will not effect any of your documents but may effect any recently installed applications depending on which restore point you use.