by pressing Ctrl+Alt+Delete at same time you can bring up task manager, which monitors all running processes on your computer, hitting the performance tab will show whats eating up your memory, sometimes closing running tasks that run in the background can help your computer run faster.
I'd advise reading up about the things you can do to improve your issues - have you tried increasing the capacity of virtual memory that is allocated to programs like executables (by increasing the overall ammount, you are preventing the computer to obtaining it from elsewhere when it exceeds the limit)
A link
-> h t t p :// windows.microsoft.com/en-gb/windows/what-is-virtual-memory#1TC=windows-7
On a similar note, by typing in the windows search/run bar " msconfig " and pressing Enter will run Microsoft Configuration, an application that allows you to choose what runs on startup, modify whats running in the background, and infact can help you identify unwanted programs (viruses etc) that might be affecting your computer performance.
A more tech-savvy might respond with better information, though these are pretty basic, helpful ideas