You should also check that your virtual memory is properly set. Right click your "my computer" icon and select properties. Note the total ram. Then click the advanced tab, click the performance settings tab, select the advanced tab and go to the bottom where it says virtual memory. select change. Right in the middle you will see initial and maximum size. Make the initial size 1.5 times the number you noted earlier. The max should be 3 times the number you noted earlier. You may have to click custom size to make this change.
As for the startup, go to start, run, type msconfig and click ok. Go to startup and you will see a list of things with checkmarks by them. You should be able to uncheck everything but your security programs. You should see something giving you an idea what the program is in the location or command column. Any of those programs you uncheck will not load at startup. However they will take an extra couple seconds to load when you need to use the program. In other words If you do not immediately need the program as soon as you start your computer, why load them. Your computer will start much faster if it does not have so many programs to load up. When you are done making your changes you will need to restart you computer. After the restart a box fo the configuration utility will pop up. Click do not show me this again. Keep in mind that any of these changes are completely reversible so there is nothing to worry about. You computer may not start up quicker the first time because it needs time to make your changes, but it should be fine after that.
Some will probably disagree with this solution but i've been doing it this way for years and have no startup or memory issues. Good luck and i hope this makes sense and helps you.