Try running CCleaner http://www.piriform.com/ to clean out cookies, temp files and such.

Then defrag your HD. You can download this  http://www.iobit.com/iobitsmartdefrag.html

Both are free and work wonders. Also make sure your recycle bin is empty. All these things can slow your system down. As for malware there is...

http://file-loader.com/Malwarebytes-Anti-Malware/

Hope this helps.

i also have the same trouble it happens and sometimes it works when i start windows the desktop freezes for a second and the background color appears for about 3-6 seconds ( no icons at all - just the background and im not speaking of the wallpaper im speaking of the desktop background color defined by skin ) until the jump to the actual desktop happens... after everything is loaded the rig is doing its job without trouble but its a bit annoying i agree but fences is way to cool to drop because of that.Its just not cool if you want to browse the world wide wup real quick  and you have to cold start your computer and a buddy is with you: i once had the question comming up "dude are u still using that pentium 2 ?!"   a comment like that makes your heart crack if you have a monster inside your rig...