I am having problem with IE8 running on XP Pro, when I try to run microsoft security to scan the computer I get message active-x can't be installed, I also do not get the yellow bar for download permission if pop-ups are blocked.

Same thing has happened for some other acitve-x downloads as well not for all though.

Please let me know how to resolve this issue

Thanks

When did the problem start? Did it ever work right?

This is often the result of firewalls not being properly configured, you may have to temporarily disable your for testing. Also, many IE problems are caused by add-ons and plug-ins, such as conflicting toolbars. You might resetting IE by going to Tools > Internet Options > Advanced, then read and understand what a Reset does, then click Reset.

Have you thoroughly scanned for malware? Just to be sure, I recommend purging the hard drives of clutter with Windows (XP or Vista) Disk Cleanup, ATF Cleaner or CCleaner. If using CCleaner, uncheck the option to install the Yahoo toolbar during installation. Before first use, go to Options > Settings > Advanced and ensure Only delete files in Windows Temp folders older than 48 hours is unchecked. Know your site credentials (user names and passwords) for sites you frequent before cleaning; you may have to login again at next visit.

Download and install Malwarebytes's Anti-Malware (MBAM) and scan as follows:

Check for updates before scanning,
Select Perform quick scan > Scan,
When complete, click OK, then Show Results,
Ensure all is selected, and click Remove Selected,
When complete, save the log in Notepad to a convenient place for future reference.

Repeat for all computers in the "Trusted Zone" of your network (your side of the Internet "gateway" - typically the cable or DSL modem).

Windows Disk Cleanup Note: One distinct advantage Windows Disk Cleanup has over all other cleaners is that it also has the option to delete all but the most recent Restore Point. This can be significant as malicious code can hide there too. But I caution this option, found under the More Options tab, should be used only after careful consideration. If experiencing a problem that first appeared within the last couple days, do not use this option until sure System Restore can not be used to fix it. If the computer is running fine otherwise, and you are doing your weekly supplemental scans and want to root out as many potential malware hiding places as possible, I recommend setting a new Restore Point, and then use this Disk Cleanup option to clear out the old points.

Many Many thanks Digerati, I have zone alarm, I have ccleaner and use it often, I also have threatfire which also scans for and clean malware and lastly I have run malwarebytes it did not find problem but I will do all you have suggested and if still have problem I will post here for your help once again. As I mentioned earlier this problem is with only some active-x and not all.
Thanks again

Asoke