Try defragmenting your computer. This process rearannges data on your harddrive so it is more efficent.
Do you have any extras installed for Internet Explorer? Like toolbars etc? They take up loading time and I have no extra toolbars; I find them unnessisary.
Running an online scan is no substitute to having your own virus scanner. Lots of online scans come up with false results to scare you into using their software. If this result came up empty it's possible you've used a geniune scanner, but better safe than sorry. It's best to use widely used and therefore tried and tested programs, such as AVG anti-virus from
www.grisoft.comYou could try using the Firefox browser from
http://www.mozilla.org/products/firefox/ I use it as I find it more efficent and secure.
You could have lots of programs schedueled to start. Look at the taskbar at the bottom right, next to the time. Do you have lots of icons loaded there? You might want to tell unnessisary ones not to load up at startup. Usually you can reload them yourself in Windows if they are needed. If they don't provide such an options, you can disable them from start > run > msconfig > startup. Look for their entry and remove it. Make sure you don't remove anything needed by your computer, such as explorer and systray. Apart from needed system programs, a firewall and virus scanner are the only things I have schedueled to start up.