The biggest affect on performance speed is the amount of RAM it has. It shouldn't be slow with 4GB RAM, so if it's got less than that, add more RAM.
For 32-bit Windows don't go beyond 4GB RAM as Windows won't be able to use all of it.
For 64-bit windows you can install as much RAM as that laptop model supports, which is 8GB
If it was quicker with Windows 7 installed, then go back to Windows 7.