Acer Aspire with Vista-can’t set up wireless – cuts out

I have an Acer Aspire 7720-6208 with Vista and my connection is the strongest – I am right by my router but it keeps switching to some other person’s network then at times I have no connection but looking at the little triangle I have a good connection but can’t access it. I did not know how to set it up so no wonder it does strange things. I didn’t even know where to begin. If Acer has its own wireless set up I want to use that one. Is there a list someone could give me that says, first you do this, then this, etc. so I can access my network which is the strongest using Acer’s and not Windows’s set up? It is probably very easy but when it oomes to wireless, I am very ignorant. Janice.