Programs that startup when your computer boots can drain your computer's memory. There are 5 web sites you can use to help determine whether these startup programs are necessary. Answersthatwork is my favorite listing. Three alternative sites are located at Pacs-Portal, Systemlookup, and Process library.
There are three programs available that attempt to automatically speed up your computer for you. SlimCleaner Free (or SlimCleaner Plus) are two different versions of the same software. The latter has more features than the former. A review of the free version is available. Iolo System Mechanic is a paid program You can read a review here or purchase it here.
This website provides instructions for determining how much memory your computer needs, since some users require more memory than others.
There are many different types of memory that are used by computers. It is imperative that you purchase the proper type. Crucial, a manufacturer of memory chips, has a small free program on its site that will determine the type of memory your computer uses. Other chip manufacturers have similar programs as well.
Windows 10 provides the ability to use Task Manager to look at how many resources have been used cumulatively over a long period of time, rather than just since the computer was last rebooted. Follow these directions to use this feature. You can read more about the Windows 10 Task Manager.
PC World wrote an article that contains many additional tips for speeding up and maintaining your computer.
Security holes are periodically discovered in both Windows and other programs that run on your computer. New software versions are released that close these security holes.
Symantec Norton Antivirus 2009-2014 as well as other programs released by Symantec sometimes prevent you from using Windows restore points. There is a workaround to this problem which is described in this bulletin.
Secunia will search your computer and look for any programs that need to be updated.
You can learn more about System Restore.
If you wish to determine the connection speed that your ISP is delivering to your house, visit the Speakeasy website which will perform a free speed test for you.