I'm trying to upload but can't and it might have something to do with my drivers

I didn't fill in the subject right so I'm doing this again. Sorry about that. This is probably not the place to ask but I just can’t find out about drivers. Or what ever it is that wont let me upload.

Is there a disk I can buy to install the driver on my computer so I can upload the sketch to my Arduino.

On my sketch, On the tools > serial port is disabled . How can I get it enabled again?

I can’t choose a Com .

I’ve been working with My Arduino uno for a week or longer trying to upload a sketch. I’ve checked things so many times I don’t even know now what I’ve done, but now it seems like I changed something and I can’t even choose a com. At first I was able to. I started with Com1 and it wouldn’t upload so I changed it to com2. Sense I don’t know what I’m doing I changed it to Com2. When I changed to Com2 , Com1 went away. After Com 2 didn’t work I tried to find the problem. In the meantime I changed to Com 3, now Com1&2 are gone And I don’t know how to get them back. And I still don’t know what’s wrong and on top of that I can’t even choose a Com anymore.

I’m fairly confused now and just don’t know what to do.

Well someone please help me with this. Please don’t be too critical.

Thank you, Gene

Operating system?