Windows Installer error message after installing SP3

I'm trying to help a friend find a solution to this problem on her computer (she has a Compaq with Win XP Home). She just installed SP3 last weekend, and that's when the problem started. There are no pre-SP3 system restore points.

Whenever she tries to open Windows Live Messenger, update Java, or add/remove programs (be it from Control Panel or using CCleaner), the Windows Installer screen pops up, sits there for maybe a minute or so, and then she gets the following message:

The Windows Installer Service could not be accessed. This can occur if you are running Windows in safe mode, or if the Windows Installer is not correctly installed. Contact your support personnel for assistance.​

I tried the instructions in Laborous' thread, but as in his/her case, after typing sfc /scannow (after repairing permissions using Dial-a-fix) I got a message asking for the Win XP installation disk - which my friend doesn't have. (Perhaps I could use mine? Her copy of Windows is legit, she just doesn't have an installation disk for it.) Tried Laborous' escape route (bailing out and rebooting), but it didn't work for me - the problem persists.

I tried Methods 1 and 4 at http://support.microsoft.com/kb/555175.
I also tried Method 2 at http://support.microsoft.com/kb/315346 (because it looked a whole lot easier than method 1), installing Windows Installer 4.5, but still no luck.

Aaaargh! Any suggestions, short of doing a clean installation of WinXP?
Thanks!

 

Did you do DAF as I suggested in Laborous' thread and check all on the first DAF page?

Check all boxes on the screen (clear any restrictions if it shows any)
Then click GO!

When the entire page is finished click the HammerHead at bottom to go to the second DAF page.

Here 1 at a time do the below

Reinstall BITS
Repair Permissions
Reset networking
Reset WMI/WBEM


Mike
Watch for any File not found or other errors and make note as this may lead to the fix!

Reboot retest!

If above don't do it do the below.

Yes you can use your SP3 CD for the SFC, DAF will do this. Hammerhead (page 2). Do SFC Purge then SFC Scan

 

Thank, Mike -
I'll try to get back to her computer tomorrow and give it another go.

 

I had my friend call the toll-free MS number for SP3 problems, and two and a half hours (and two sessions) later, tech support solved the problem for her. She said they had her install some remote assistance program, and then they "messed around lots" with her registry.

In any case, thanks for the suggestions, Mike. I've now got DAF saved on my own computer as well!