The following are ways to optimize your computer and increase overall load times and memory usage. I have been doing this for several years now and have found these methods very effective on customer computers. This is the true "Free PC TuneUp"!
CCleaner is a program that will clear out your computers temp files and fix your registry. I run this program on every computer i receive regardless of what it needs.
Msconfig is a windows tool that is used to configure startup programs. Search for it on your computer or start/run/msconfig. Click the startup tab and from there you can configure what programs you actually use when you start your computer. I usually only leave the entries that relate to drivers or the computer, though you do not have to. If its an entry for a program like quicktime/skype/google/messenger/adobe/office etc. I uncheck it. You can drastically increase your startup time and overall computer performance using this tool. This is one of the most useful tools in windows.
3. Disk Defrag
Defragmenting your hard drive will increase your read/write times to your hard drive which will increase your performance. Check out Defraggler by piriform, the same company that makes CCleaner. I use it along with the standard windows defragmenter every couple of months.
If you have a desktop computer make sure it is free of dust. Spray it out!
Reset your internet explorer to all defaults in internet options if you use it.
Check what plugins and addons you have installed in firefox! Remember everything you have added increases the amount of memory needed to run firefox. If necessary reinstall firefox or reset it to get a fresh fox with no additional addons or plugins. The difference in memory usage can be huge sometimes!
Update your computer with windows update! Stop ignoring it, I know you do!
Uninstall programs you do not use.