The best option is to get any and all files that you want to keep off the computer and then just do a system restore. This will remove EVERYTHING off the computer and it will most definatley run faster. If your computer has all these preinstalled programs that you dont want, get the program Decrapmycomputer and it will remove any unwanted programs. Now in this day and age, if you have 4gb of ram its useable but its best to have 8gb if you have only 2gb you need an upgrade but anywhere from 6-8Gb of ram is plenty and useable. If you have that much ram and you restored it and its still very slow, it could be your hdd. An SSD can be a pricy upgrade (depending on how large you get it) but its totally worth it.
Hope this helps any people who come here in the future looking for answers!