that definitely sounds suspicious and similar to what the antivirus xp scams do they mimic the look of the microsoft security center.
I would also first make sure you have the most updated version of malwarebytes (update prior to taking it with you) and run the full scan on her pc. Depending on what that reveals, then try to run an online virus scan to make sure her's on the pc has not been compromised. I would also do a check with secunia inspector to see if the rest of her stuff is updated, many of the malware infections are now coming in through holes in apps like adobe and java so keeping every thing updated not just windows is essential. Secunia has the online scan version or the one that can be installed on the pc, I would teach her to use that regularly to keep updated, and once malwarebytes is installed show her how to update and run full scans weekly.
Secunia Online Software Inspector (OSI)
FREE Online Virus Scan

and also a good idea is to put WOT on the pc and instruct her not to visit any of the sites that are not green
Free Internet Security WOT Web of Trust

and of course check her security center and make sure her vista firewall is on and working as well as her AV product and that her AV is fully updated and doing regualar scans.

If malwarebytes finds any rootkits then you have more to deal with. If any infections at all are found and removed do not do a system restore or they will be back. Do not clear any restore points out either, if she should need further help they may need restore points and those restore points will cycle out, once all is fully clean and functioning that can be done but is not essential since they do cycle out

The first thing to do is run Malwarebytes you have to look at the malwarebytes log to get an idea of what was removed and what was infected system restore may already be infected, in malwarebytes it is called System Volume Information. That's a start.

The next thing to do is run a hijackthis scan and post a log.

Post both logs here I can easily decide if they need additional help an will direct them to that help..

Doing this any other way by just running scans is guessing, an fumbling in the dark, just because the symptoms go away does not mean everything is ok.

Need help ask...

Thanks. I already made sure that I have the most recently updated versions of Malwarebytes on my thumb drive along with the latest version of Superantispywareblaster. I'll also take along the others that RC suggested. Will make sure she does not try a restore---I doubt if she even knows about that. Since I use both WOT and Secunia PSI, I'll show her how to use those. She is the kind of person who usually will not go happily clicking here and there, so I don't know how this may have happened.

We have had so much rain in the past hour that I doubt I'll get to her house before tomorrow. I had already told her to turn off her computer and do nothing else. I'll call and reinterate that advice. Will let you know what happens.

Don't over look "Safe mode with networking" if the user can't connect to download malwarebytes an the hijackthis program.

Here is a link that might be useful: HijackThis

Vista, when a user is logged on as a normal user account, will pop a login/password request for elevated authorization to do things that require administrator privileges.
It would usually give me a selection of account names to choose from and then I will enter the proper password under one account name that has admin rights to proceed.

It might be prudent to see if McAffee is up to date and running or if it has been shut down by intruders. Also check to see if Windows Defender and the firewall are doing their job or turned off. Windows Defender is on Vista machines by default.

Mikie may be right an there is nothing wrong

I just got off the phone with my friend, and she said she was checking e-mail when this popped up, but she hadn't even opened an e-mail at the time. It could be that Mikie is right and perhaps she used the wrong password for authorization for whatever. Anyway, she said she checked and her McAfee is up to date, so I told her to stay offline and run a scan with it and to check to make sure her firewall is activated. Maybe this will turn out to be nothing after all (I hope). She can still make use of WOT and Secunia and get into the habit of scanning regularly with Malwarebytes. She tends to get flustered rather easily.

Sounds like the mail on one end or the other may have had a snafu and wanted her isp login/password to check mail.

I had the same problem. After using malwarebytes and other scanners I gave up and the guys at delta computer assistance remotely accessed my system and fixed the problem. They are awesome, check them out.

www.DeltaComputerAssistance.com

Here is a link that might be useful: Delta Computer Assistance

Guy probably has a good place to buy Hookah's too !

Check out megeek2's "my page". Registered this morning and I'll give you two guesses what he lists as a home page...

Hmmmmm!

Well, after some delay, I am going to her house Saturday morning. I'll post afterwards as to what we were able to find out.

Ran Malwarebytes complete scan; nothing found but some adware in registry which we deleted. She had already run a complete scan with her McAfee Security Suite and found only some tracking cookies. Online virus scan turned up nothing. I went online and opened Vista Mail which began to download e-mails from several days ago. Opened an e-mail with no difficulty. Went to a couple of web sites with no problem. Vista SP1 has never been installed, and I noticed the date of April 28 on it. I think that is what was triggering the request for user name and password, since it wants to install. I told her to install it ASAP as soon as all her e-mails are downloaded. She is on a very, very slow dialup connection, and this is probably the source of all her difficulties. That's all it was previously when her McAfee was trying for days to download updates. I told her to bite the bullet and get a Verizon cellular broadband modem. She is less than two miles from the tower where I get my connection and has a perfect line of site for that. It will cost her something, but will cure so many of her headaches. She can afford it, too.

Forgot to say "thank you" to all who offered help, and for the heads up from Mikie about Vista and administrative permission. My friend is really cautious, so I could not understand how she could have picked up any malware. But when something unfamiliar happens, she tends to panic. I think if she gets SP1 installed okay, she'll be okay. . . . at least until the next time. LOL!