Dennis wants to upgrade his HP laptop. He wants to double his RAM and install an SSD. Will that help? Leo says that if he has a fast enough bus for the computer, an SSD will certainly speed things up, as an SSD has zero latency. Reads are very fast. But he won't get as much as a modern laptop. It'll still be noticeable. And he'll get at least a 10-20% boost by doubling his RAM.
Since he can't replace the processor, this is the best thing he can do to keep it going. And reinstalling his OS will definitely make it faster. Should he do it all at the same time? Leo would recommend installing the RAM, then reboot to make sure it's seated correctly and booting up properly. Then he can go ahead and install his SSD. It should come with a cloning program to clone his spinning drive.