I need to find the drivers for my computer?

I need to find the drivers for my Dell Inspiron 1420 Notebook. The Service Tag is 8PRLGF1. It is a 32 Bit and I am running Internet Explorer. I replaced my old internal hard drive with a new one today and the driver for my wirelss card said that the computer was not compatible. I searched on Dell and it said the same thing. Also I have no sound(what that driver called?) and the scroll left/right and up/down on my mouse(what's that driver called?) does not work either. I am sure there are other drivers that I need as well. I really need these drivers installed as quickly as possible. If any one has any suggestions I am open to them all. I only ask that it is pretty detailed. I am not that computer literate. I appreciate it. Thanks.