Welcome to testmy.net
dendrophilia. First try the basics this topic will go over those, and simplify them for you.
http://www.testmy.net/t-2097. Now that we have the basics covered, where in the house is the wireless router located, and then where is your computer located? Older routers could interfere with cordless phones on a 2.4GHz freq. So It's important to not put a router next to anything cordless I.E. a cordless phone. Next accessing your routers setup pages. By doing this you can change most of the settings that the router need to configure itself. Example: Wireless signal strength, if you are far away from you router try setting it at the max setting. Next after you've configured your router, try setting up a secure line between you and your router. Doing this ensures that you and only you are connected to the router. Usually requires you to make a 'security key'. Everything that I've discussed, should be within your manual for the router itself. Just go from the basics to the advanced, if you need help, that's what were here for. Welcome to the forum again. ;)!
Got rid of the other one for you 