Internet Explorer connection problem

Tustastic

Hope someone on here can advise. I haven't been able to get onto the internet for a couple of days from my home desktop PC. I get a message that I'm connected to the internet, plus the usual icon at the bottom of the screen. However I can't launch either IE7 or Firefox. I am able to send and receive emails via Outlook Express.
I get an error message in IE7 saying that there is no ethernet cable connection. I've checked and tightened all the cables however no success in opening the browsers.
Is there anything else I can do?

aliEnRIK

Can you get on in SAFE MODE WITH NETWORKING? (Keep pressing F8 at bootup)

Are you using a router? Have you tried rebooting or resetting it?

aliEnRIK

If you CAN get on, id guess your machines infected

Download MALWAREBYTES (Click 'DOWNLOAD NOW')
http://www.download.com/Malwarebytes-Anti-Malware/3000-18510_4-10804572.html?cdlPid=10997763
UPDATE and FULL scan
Post the log here after its deleted everything

Download HIJACK THIS (Click 'DOWNLOAD LATEST VERSION')
http://www.filehippo.com/download_hijackthis/
reboot
SCAN and post the log so we can see whats running
(MUST be run in 'normal' mode)