What is wrong with my computer?

[Heybail]

Last night when I got home I turned on my laptop (It's an HP Pavilion dv5-2135dx that I bought in November 2010). When I tried to get on the internet it'll load my homepage but if I try to go any further I'll either get a "Internet Explorer cannot display the webpage" or a screen like the attached picture (depending on the website). There are point where I can get a page to work for a couple minutes but then it goes right back to not working.
Last night I got a notification from Norton Antivirus that my software was out of date, so I updated it and it did some autofix on my internet which fixed it for the rest of the night.
Today when I turned it on, it started doing the same thing with my internet again. I've checked that my internet is on, the wi-fi is on, and the WLAN is on on my computer. Also, I did a scan and I don't have a virus.

Does anyone have an idea what is going on or how I can fix it?

Thank you!
P.S. I don't think it's the internet itself because my mom is having no problems on her desktop and I am still picking up the wi-fi on my cell phone and iPod.

[chandra]

Try this .
Download malware bytes from this link and scan your computer . After quick scanning, if there are any malware, it will show you in the scan and ask you to click "show results". Please select all those and remove it using this tool.
Then reboot and scan full scan, and delete the malwares. These malwares come with bundled program with the downloads from suspicious sites.
Download only from secured sites like majorgeek.com filehippo.com , the required downloads,else choose the author sites
If these do not fix, system restore is the only other option to get rid of these popups.download the free version.
http://www.malwarebytes.org/