virus please help

I have a virus on my computer, it wont let me do anything once i enter my log in password it just loads for 1 min and then a screen pops up with a message, it has a big CSIS (canadian inteligence services) logo and header at the top and dispalys my internet provider name (rogers) and my IP address. then says ATTENTION! you have broken the laws of the Canada! goes on to say my computer was used to look at child porn and bestiality images/vidoes and has been sending out terrorist messages (havnt done any of this) and i need to pay " &$100 " to have my computer unlocked.

Im sorry i really know nothing about computers, and the place i bought my computer 3 months ago (bestbuy) wants $211+tax to remove the virus and will take atleast a week the dude said. I really cant afford that especialy since thats like 1/3 the cost of the Toshiba laptop itself. I was wondering if anyone can help or has any suggestions at all.

 

Hey Thanks for the reply man. i was able to get it into safe mode w/networking and then followed some directions given to me from a guy in the IT dept. at my work and was able to get the computer working again, i just searched for ".exe" and delted the file that came up. then rebooted. but i guess that dosn't actually fix the real problem. i was told to delete and reinstal the operating system to make sure everything that could be hiding is gone. is that the same as reseting to factory settings (option from start menu) i can now go into safe mode or safe mode w/netowrking or command promt or normal mode, also a option for repair. what would be the best way to go about doing this? again im sorry i know jack shi* about this stuff. but now learning haha.