If you have WinXP with a fairly good hardware configuration, I'd suggest not to use these programs. IMHO modern systems don't require them.
Remember you can d'load TRIAL versions of these so-called 'memory optimisers' to see if it makes a difference before you buy. Beware of offers that want to take your money first even if they offer a refund if dissatisfied. To d'load a 30-day trial of MemMonster - click here.
I've posted links to over a dozen similar programs here click here, so you have more choice. For even more choice - click here. Let's know how you get on. G