To speed-up access in My computer do the following steps:

In the Folder options uncheck the automatic search for network..
Mark the Do not cache thumbnails

If you are not using common task then disable it through:
Mycomputer>properties>advanced>settings (performance) and uncheck the use common task in folder....also uncheck the following-

Animate Windows....
Fade options..
Show shadow under menus/mouse pointer
Smooth edge of screen fonts.