Windows defender is a free spyware/adware protection program from Microsoft so any pop up demanding that you pay for it is a scam. Does she have any antivirus software installed on the PC? if so run a full scan and see what comes up. If not download the free version of AVG and run the scan here
http://download.cnet.com/AVG-Anti-V...l-10044820&subj=dl&tag=button&cdlPid=11014801. If you cant connect to the internet on that PC than download it on a different one and put it on a usb stick.
If she is not on the internet then i would check her network connection is enabled and connected (go to network and sharing centre). If enabled and connected check if skype, msm messenger or any other program which uses the internet works. A good way to test if the PC is on the internet press start and then type cmd.exe and the press enter. You will see a window with a black MS-DOS like interface. Type the following EXACTLY (inside the code box):
Code:
ping [url]www.google.com[/url]
then press enter. If all 4 packets theat were sent were received then this means the PC is connected to the internet. If the result is negative then i wuodl check the method of connecting to the internet (wifi, cable, moden ect in Network and Sharing centre) If she is connected to the internet check if there is any third party firewall on the PC which is blocking internet access. The easiest way to remove this is to uninstall the firewall application as windows firewall provides adequate protection. I have come across viruses that block internet explorer from accessing the internet so a short term fix would be to install firefox(download on different PC). I would recommend chrome BTW but you need a browser that works to install it.
There is so much that could be wrong but i think i have covered enough for you to be know what might be causing the problem. Hope this helps