It's obvious the Anti-virus client she had didn't do it's job. If it was Norton or McAfee, then they are specifically targeted to shutdown in the background so the malware (malicious software) downloads undetected - until that authentic-looking Windows screen pops up.
What happens then is that
more adware, spyware, and Trojans download - until you buy it. Then, the creeps have your credit card info - and then you're done. Even then, there's no guarantee it works to remove anything - it's just a front for a ripoff.
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First, download
CCleaner for free at download.com - this will get rid of Temp files which will slow down the next two scans.
I have the perfect cure for Antivirus 2008 and 2009:
Malwarebytes' Anti-Malware 1.30 free at download.com
I've used this on several machines with great success. Most have become infected by Facebook and YouTube.
Also,
Super Antispyware Free is very effective, too and should be used after the above tool.
NOTE: Be sure you update each product immediately after installing and
before using.
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Once you do all that, grab bitdefender antivirus for $29.95 (for use on up to 3 computers) and use that for real-time protection. It's highly effective and "off the radar".
Then, put the shortcuts to the above programs into a folder on the Desktop called "Maintenance", and then run those programs every few weeks.