My virus won't go away

I had 10 viruses a while ago and my antivirus found them but my computer has never been the same since. I can only get my browsers to work for about half an hour and then i have to close and reopen it. Even when it is working if i try and open a new tab they never load so i can never click on links that open in a new window or tab. Is this to do with a virus?
Every day i got a popup saying java oracle america wanted to update but when I did a scan they stopped. I deleted a quarantined tracking cookie from my antivirus the other day and as soon as i did this the update for oracle america came back. Does this mean deleting it from quarantine brought the virus back? And what can i do about my browsers, it happens for both internet explorer and google chrome.
Thanks