DNS cache may be the root cause of the brief DNS issues that are maintained by Windows XP for performance reasons. If you are having difficulty getting even a single website online, you must use the 'ipconfig' command to delete the DNS cache via the 'flushdns' transfer.

DNS cache is the temporary storage of information from previous DNS lookups on a machine's operating system or web browser. Keeping a local copy of a DNS lookup allows your operating system or browser to retrieve it quickly, allowing a website's URL to be resolved to its corresponding IP address much more efficiently.