I have Security Update for Windows XP (KB908531) installed in my com and ever since I noticed verclsid.exe runs everytime i open a program.
After i restart my com and logged in my user, a window pops out asking me to reactivate my product key.
I did not see my taskbar so I assume explorer.exe was not allowed to run.
None of windows shortcut keys worked. ( ctrl+alt+del, etc.)
With nothing else better to do, I typed everything i saw at the back of my CPU(on the case) in it.
I was surprised the product key shown before i edited it is completely different from the one at the back of my CPU.
Then i pressed the retry button, and waited...and the "Activate Windows" window said "Incorrect product key".
When I press Remind me later, windows just logs off.

What should I do?

I have a hunch that someone else bought a pirated copy of windows XP and coincidentally used my product key. Verclsid.exe may have scanned my com and did this since there are 2 coms using the same product key.

Have a look here for more info on that update , and resulting problems because of it:

http://www.pchelpforum.com/windows-x...clsid-exe.html

And give this app a try to find the currently used XP key on youre pc since you mentioned that the key on the sticker on the back of the pc was different:

http://www.magicaljellybean.com/keyfinder.shtml

And see if you can activate windows again with the key it shows.

I have read that post before and I'm sure my IE is working fine.
I have that keyfinder too and like I said, the one in shown was different from the one on the case of my CPU.

I have used that keyfinder to get windows xp product key from my other computer (a valid one) and tried to use it to activate, but windows said it was unauthorized too. Was planning to change the product key back to my first one after the activation becoz microsoft does not permit 2 coms using the same key unless I show them more money.
I have also used autorun.exe and compared my entries with the other com. If u want to have a look, I can post a screenshot here.
I have compared the c:\windows\system32\oobe folder of two coms and found that my com has an extra folder (hpoobe) which is 2.93MB and less one file (OOBEINFO.OLD) 1 KB.

I just uninstalled KB908531 and used hijackthis to remove the keys which are infected. I'm unsure of which caused this huge problem but I would like to find out. I should have done 1 step at a time.

After the restart, my com logins smoothly. I ran oobe/msoobe /a and windows said that windows is already activated. Then i ran keyfinder and found out that now my com uses a product key from another computer. I used magicjellybean keyfinder to change the prodect key to my original one but it said I have put in the incorrect key. Oh my god things are getting too messy I need to change to key back! Currently I have disable windows update until I have my key changed back.

Now i guess i can disable processguard from protecting explorer.exe from being read n terminated by winlogon.exe and msoobe.exe. Looks like Microsoft Windows is not that secure seeing that i still can login even though my windows is not activated.

Sigh.....the windows activation window came up again.
The only thing i did was install and uninstall wincustomize programs such as thememanager.exe, logon studio, cursorXp, etc.
I remembered uninstalling those programs too before i got this problem 3 days ago.
If it wasn't for processguard i wouldn't be able to login........
I'll just post my processguard log here, hope u guys can find something..

At 11:03:58 i uninstalled security update for windows xp KB098531 and restarted my com.
I successfully login without any problem at 11:16:06.
I restarted my com at 14:01:41 adn then i had the login problem is back again.

I have checked http://support.microsoft.com/kb/918165/en-us and microsoft never said that KB908531 could have caused this problem.

Hi again,
I was puzzled on some logins which I did not encounter the windows activation in in these 2 days.
So I just did a research and restarted my computer for 7times. Started from 9:45pm and ended at 10:56pm (GMT+8 ).
In total I logged in and logged off my user 16 times.
The windows activation window did not appear in my 2nd (9:50), 8th (10:10), and 16th (10:56).
I saved screenshots of the tasks running on my 8th and 16th login and compared them.
I found out that whenever I login to my user normally, the more distinct differences is I do not see logonui.exe (USERNAME-SYSTEM) and msoobe.exe (USERNAME-User) which runs when I have to activate windows.
I have also compared the services started in a few login attempts and found nothing different.
Based on that now I think the problem lies at these two files but i do not know what it is. I have ran online malware scans, panda scan, norton scan, ediwo, hijackthis...........Now I'm gonna check all my logs and see if I can see anything else.
I opened taskmgr and clicked end process on logonui.exe nothing happened. Then my com auto logged off after i ended msoobe.exe. I feel that something is trying to trigger msoobe.exe to launch whenever winlogon.exe loads my personal settings. The only thing is I do not know how to see what processes run while logging in.