Windows Update doesn't work anymore.

Windows Update doesn't work anymore.

I always check for windows updates manually.
When I go to the update site it asks me to try to install windows update software ( by Microsoft). When I click on to install or not to install it waits a bit and then the  another page says:
" Internet Explorer has closed this webpage to help protect your computer
 A malfunctioning or malicious add-on has caused Internet Explorer to close this webpage."

This happens even if all add-ons are disabled!
I  even went to the  properties-performance options-data execution  prevention and selected the turn on DEP for all programs and services except those that I select, in which windows explorer appears and I check it off so that it's turned off on windows explorer ( yes, I rebooted after making the change) as per the instructions about DEP if you're having problems.

I'm using Windows XP Pro SP3  and NIS 2010 with all the updates.

I haven't had a problem with windows up[date before and I check it once a week ( every Saturday Night) .

I've also ran full scans with NIS 2010, Malwarebytes and SuperAntiSpyware all fully updated which came up clean.

I haven't tried disabling NIS2010 auto protect yet, since I'm not sure I should in this situation...