Try system file checker:
start_run sfc /scannow
Try a different email prog: there are lots of freeones out there, eg Pegasus, Calypso email, Eudora to mention a few. Or Becky from click here which costs about US$40 - I use it and find it excellent.
Remove OE using the add/remove control panel and then log on to windowsupdate site and install it from there.