If you run the "snipping tool" from the start menu, you'll be able to take screenshots and then attach them to this site using the paperclip icon, after clicking the green post reply button.
To find the place Dave suggested, type "msconfig" in to the start menu search box and press enter. Then, click on the startup tab and take a screenshot using the snipping tool.
I would also suggest loading task manager (right click the task bar then click "start task manager"), then click the processes tab and sort the list using the memory column. If you could also attach a screenshot of that it would help.
If you need any more help on how to do this, then just say and we can explain in more detail.