Cant believe noone has mentioned the number one problem with laptops.
If you have pets (or just general dust build up), your slow issues could be down to clogged fan and heat sink.
My sister had same problems and was about to buy a new laptop (CRAZY). So I took a look and dog hair had created a coat across the heatsink fins. This had the effect on causing the speed stepping to kick in and was dropping the CPU down to 20MHz. It would take 30 to 40 mins to do anything on it.
Once cleaned out, the machine was back to as new speed.
I have 8.1 running perfectly fine and fast on my daughters single core 64bit CPU and 2GB RAM. So cant see it being your single core CPU at all. Hell I even had WindowsXP running on a slow machine with only 32MB RAM.
