Once in a while, when you start Windows XP Professional, one or more programs appear to be uninstalled. If you restart the computer, the missing program(s) may appear.
This behavior will occur if the programs(s) are assigned by Group Policy and Offline Files are configured for a DFS (Distributed File System) path like <Your Domain>\<Share Name> and <Your Domain> is not reachable.
When you experience this behavior, <Your Domain>\SYSVOL is offline, causing Group Policy to not be applied, resulting in programs that are configured to be removed when the policy that assigns then is not applied being removed. If you restart your computer and <Your Domain>\SYSVOL becomes available, the programs are reinstalled.
To workaround this behavior, either configure the SMB shares in your domain to use <Server Name>\<Share Name> syntax, or disable the Offline Files feature for all DFS paths like <Your Domain>\<Share Name>.
To help prevent this behavior, make sure that the network adapter drivers on your network are current and that the Network Location Awareness (NLA) service is started.