Microsoft Windows XP won't allow you to uninstall Internet Explorer or Outlook Express. How can you fix them or even reinstall the programs if they become corrupt?
Internet Explorer has encountered a problem and needs to close.
This one can be pretty frustrating. Sometimes you can fix this without having to completely re-install IE. Try these tips first and if that doesn't work, then you can try re-installing IE.
Use System File Checker to scan for changes or modifications to Windows protected files. If any files were overwritten or deleted, etc, SFC will automatically retrieve the correct version of the file and replace it. You can run SFC by going to Start, and then Run, typing in CMD and then typing sfc /scannow in the command window.
Re-register Internet Explorer DLL files. Click on Start, then Run, type in CMD (or use the Windows key 
+ r) and then type the following lines and press Enter after each one:
- regsvr32 softpub.dll
- regsvr32 wintrust.dll
- regsvr32 initpki.dll
- regsvr32 dssenh.dll
- regsvr32 rsaenh.dll
- regsvr32 gpkcsp.dll
- regsvr32 sccbase.dll
- regsvr32 slbcsp.dll
- regsvr32 cryptdlg.dll
If you don't yet have the very latest version of Internet Explorer or Outlook Express, you can fix many problems by visiting http://windowsupdate.microsoft.com/ and updating to the latest version. If you're already up to date, however, the site won't let you reinstall the program. You need to fool the system into thinking you don't have the latest version.
Please, back up the Registry BEFORE you attempt to edit it. To do this, after regedit starts, in the 'Registry' menu at the top of the window click 'Export Registry File', give it a name (I usually use today's date, i.e. 20040509), then click the 'Save' box. Worst case, you can use regedit's 'Import Registry File' function to restore the Registry but, if you're careful, you won't have any problems.
Internet Explorer Run REGEDIT from the Start menu's Run dialog and navigate to the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{89820200-ECBD-11CF-8B85-00AA005B4383}. In the right-hand pane, double-click on the DWORD value IsInstalled and change it from 1 to 0 (either Decimal or Hexadecimal). Close REGEDIT and go to the Windows update site again. Now it should let you "update" IE.
Outlook Express Run REGEDIT from the Start menu's Run dialog and navigate to the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{44BBA840-CC51-11CF-AAFA-00AA00B6015C}. In the right-hand pane, double-click on the DWORD value IsInstalled and change it from 1 to 0 (either Decimal or Hexadecimal). Close REGEDIT and go to the Windows update site again. Now it should let you "update" OE.
If updating to IE 6 or OE 6, or if reinstalling them using this procedure does not cure your problems with IE or OE, then your problem is somewhere else. Sorry. 
Rockport, MA 01966