HELP!!! Anti software advertisement won't let me do anything on my computer!

HI..

Since about 2am last night, some sort of an antivirus software blocked me from accessing the internet.

I went to bed thinking that the the issue will be solved by the morning itself.

This morning, I turned the computer on an realized that the problem is worse than I thought. The advertisement won't let me utilize any functions on my laptop.

It keeps on having different warning messages.. Too much to remember and since I'm can't use my laptop right now, I can't give a detail of the description. Does anyone have an idea why I'm getting these messages? One thing I remembered was something about Trojan?? Thank you very much for your help!