There are many things that affect the performance of your system. AvaPA is designed to work on very low specification systems and demands comparatively lower resources over other similar applications.
You will experience lower performance the older your network and PCs get.
There are a number of reasons why this happens:
If the hard disk is full(ish), then it will slow down. It's not because of the weight of programs in the literal sense. It is because it's quicker to get stuff at the beginning than the end - often by a considerable margin. As a rule if the disk is over 80% full (known as the 80/20 rule) performance will suffer. Running "Disk Cleanup" may help. Disks are cheaper than they were even a couple of years ago (and faster too). There is probably space to add a new one if you have not done so. Take care however as there is more than one type of connection for your Disk. In common use there is ATA which is a large connection with lots of pins and SATA with is a small connection with few pins. They do not connect to each other but both are available. There is also a connection called SCSI but this tends to be used in more expensive computers like Servers.
If you have the basic memory in your PC it will definitely benefit from more Memory. Memory comes in two flavours: RAM and Hard Disk. RAM (Random Access Memory) is often referred to just as Memory. It is quick (a thousand times faster than your hard Disk) but its also expensive by comparison- may be a hundred times more expensive per unit of Memory. Your computer will load what in needs into RAM as it needs it. As Memory is used up: the stuff it needed last is put back on the hard disk. The more memory a computer has then the less often it needs to load the old stuff back on to disk. You can find out how much Memory your computer has by going to the start button and selecting my computer - right mouse click and you will see a list containing the word properties at the bottom. Click on this. Bottom right it will tell you how much memory is in your computer - 1GB is a good amount for XP (although it willhandle and improve performance upto 3.5GB). For Vista 3GB is what you should settle on. Windows 7 machines tend to come with 3GB anyway these days.