How much RAM? You may need more with an Atom.
Do you still have the HP bloatware after an in-place Upgrade? It is the worst of any make, with a wireless mangler that adds greatly to Startup and is inferior (like all factory utilties) to Windows 7 built-in wireless manager.
Go to msconfig>Startup and uncheck everything except AV and gadgets if you use them. Reboot and see if any write themselves back in, turn them off in their program preferences or uninstall them.
Next in msconfig>Services choose "Hide all MS Services" and see what's running that you didn't start. Uncheck everything, reboot to see what writes itself back in to tame it.
If this doesn't help, update your drivers
. Check optional Windows Updates.
Monitor the logs and system Resources: troubleshooting steps
Let us know how these steps work. There are more.