Windows Security Center Alert : Spyware.ISpynow

About a week ago, a popup from Windows Security Center came up and said "Windows Firewall has blocked activity of harmful software.

Name: Spyware.ISpynow

Risk Level: High"

It then asks if I would like to enable protection, and takes me to a website to buy a bunch of stuff.

Since that popup, my computer (especially the internet) has been running especially slow. And now when I go to open my internet, my homepage (msn.com) will open just fine, but when I go to type in any other address and hit enter, the address changes to (http:///) --> 3 slashes; and says the address is not valid. The websites saved to my favorites will open, but none of the pictures are there. And other sites will just give me a feedback of "Internet Explorer cannot display the webpage".

I do not have any anti-virus installed on my computer, nor do I have a firewall (for some reason it has been turned off and I cannot get it to turn on).

I am writing this from a friend's computer (seeing as my internet won't work). However, I have HijackThis installed on my computer from a previous problem.

I am not very computer saavy, so you will have to sort of give me step by step instructions on what to do. I have already run hijackthis once, and have a logfile open. Let me know if you can help me.

Thanks!