Malware security hijack- "xp security center"

I'm having a series of security related problems on XP all of a sudden.


First I get some questionable popups "Privacy threat! spyware intrusion detected" &c. Second, I cannot enable my firewall even thru command line scripts (even though it read back OK).
Thirdly, the security center is demanding my license to fix trojans, but it does nothing when I enter it. Just more popups.

Thirdly I am getting FIJ.exe running, but I cannot locate it in the registry.

fourthly I cannot run malawarebytes or any software executable from a flash drive.

I ran the latest Malawarebytes, found and fixed some files, but not resolved.
I ran the ATF Quickcare found and fixed some files, but not resolved.

please help!
Trying to cure cancer and global warming with this PC
/kidding

 

I had the same problem.....couldn't fix anything, couldn't save anything and it happened out of the blue. I ended up wiping my drive and doing a whole new reinstall. It was determined later, that a wireless router I had bought from a friend had all kinds of crap imbedded in it from its previous owner. You haven't added a router recently have you? Just a thought.....