Pc Extremely Slow, Redirected To Usuc.us Site

Hi, My computer has started running extemely slow. I believe it started in March but I could be wrong. It hangs and everything runs slow. When a page is closed it is as if it is being peeled very slowly off a window. Just recently it has started to reboot itself and then come back on while I am working. This happened the last time when I clicked on my anti-virus icon. Also, when I did a scan today I left it running while I left to visit family and when I came back home it had not progressed beyond the spyware portion and had taken nine hours. I restarted my pc and tried again and this time it worked When I sign on it redirects me to the following site, usuc.us/2/to_peakclick.html. This sometimes changes to speedyinfo.com but the pages are blank. Accelnet, which is included in the MSN connection center, also appears to not be working as it is supposed too. When I click on the world icon in the lower right corner, there is only a little box that appears which shows connection speed, connection center help, status,acceleration speed and about connection speed. I think there is supposed to be a place to disconnect but it is not there and I don't think it is supposed to be just text. Also, if I am not connected to the internet, my sign in box keeps appearing no matter how many times I close or minimize it. I have tried to get help at another site but I had to go to the hospital during a period when they were trying to help and now I can't get a response to my last post. I was asked to remove some items by ticking them on the hijackthis log and I did. I could provide those if necessary. Now I can't get a response and I don't know what to do. Can you help me? Here is the header for the hijackthis log I just did. Logfile of HijackThis v1.99.1 Scan saved at 2:57:56 AM, on 7/5/2007 Platform: Windows XP SP2 (WinNT 5.01.2600) MSIE: Internet Explorer v7.00 (7.00.6000.16473) Thanks