Windows security alert trojan problem

Hi. I keep getting Windows Security Alert pop-ups and I cannot open My AVG 8.5 scanner or anything else for that matter. I cannot open any software even in safe mode. For a while yesterday I got Internet Explorer to run by clicking TOOLS-INTERNET OPTIONS-CONNECTIONS-LAN SETTINGS and unchecking the proxy server boxes. Today I can't keep the checks out of the boxes. Is there a way to manually fix this so I can at least use that Microsoft One Care Safety Scanner. I used it yesterday and it cleared up 8 mal wares and the registry issues I had. But surprisingly they soon returned. I cannot open my e-mails so I will have to check in on the BBS boards for any of your answers. I hope you can give me simple step by step instructions to fix this or at least get my IE to work so I can scan at Microsoft One Care again. If you know of any online scanners that do not require me to open software from my desktop, that could be useful too. I am currently using Mozilla Firefox to access the net and that will not work with the Microsoft One Care Safety Scanner. Thanks!