Storage/1998 too old?

[BigMick]

I am by no means an expert but I have always enjoyed drinking wine. I typically drink red wines and it seems I always keep more on hand than I drink in a timely manner. I see many questions on the board regarding the age etc... of wine which raised a concern for me. I store my wine in a wine rack but unfortunately it is at room temp. as I don't have a cooler place to store it other than the refrigerator which isn't big enough. I was about to open a bottle of Gallo of Sonoma Merlot 1998 when I notice that on the inside of the bottle it appears there is sediment stuck to the back of the bottle (the side that has been down in the wine rack). Is this wine any good? What is the best way to store wine given my situation. I have a Pinot Noir 97, a 98 and 99 Chianti and an 02 Cabernet should I be concerned about these as well? All the other reds in my collection are either 03 or 04 so I hope there is no concern there. Any and all information is greatly appreciated. Thank you in advance.