Get this error message upon start up and when trying to open programs such as media center and quickbooks

Hi bigchuck39,Did you make any software or hardware changes on your machine prior to this issue?We usually get this error message if.Net Framework is corrupted or not working correctly.You may follow this link and check if the issue persists.Method 1You may configure the computer in clean boot state and check if the issue persists at startup. It will start Windows XP by using a minimal set of drivers and startup programs and helps to eliminate software conflicts.The following link has steps showing how to perform clean boot:http://support.microsoft.com/kb/310353Note: Please ensure that the computer is set to start as usual by following the section ‘Steps to configure Windows to use a Normal startup state’ from the article: How to configure Windows XP to start in a "clean boot" state: http://support.microsoft.com/kb/310353Method 2a) You may also try repairing.NET Framework and check if it helps.How to repair an existing installation of the.NET Frameworkb) If it doesn’t help,you may use the.NET Framework Cleanup Tool to uninstall the installed versions of .NET Framework. Thereafter, try to install them manually. For more information, refer this link:When you try to install an update for the .NET Framework 1.0, 1.1, 2.0, 3.0, or 3.5, you may receive Windows Update error code "0x643" or Windows Installer error code "1603"Hope the information helps. Please post back and let us know.RegardsDebleena SMicrosoft Answers Support EngineerVisit our Microsoft Answers Feedback Forum and let us know what you think.