computer help: desktop freezing

[cloud1161]

im running a windows vista 64 bit system.  when i go to click any of my desktop icons, my computer lags really bad and i eventually have to turn it off manually.  when i open the same program or file from the start menu, it works fine for a few minutes then eventually ends up doing the same thing.  i really dont want to do a system restore if i could help it.  any ideas on what the problem might be?  ive run malwarebytes and adcleaner several times, but they dont seem to help.