RS232 cable + USB cable?

Try this website: http://www.tigerdirect.com/applications/SearchTools/search.asp?keywords=USB+to+RS232+cable+

Yes.

http://www.google.co.uk/search?q=rs232+usb

Cheap & easy to use (some are plug'n'play, some need drivers that come with them). If you're using a laptop, make sure that it's compatible (some of the cheaper ones are limited when used with a laptop, and won't work with some PLCs).

When installed, it will look just like a COM port on the PC/laptop.

The short answer to your question is yes.

I am guessing your pc doesn't have an rs232 port. If this is the case and you want to use a usb to rs232 adapter to work with a device that only has an rs232 interface then you should be able to find something that works.

I have used these cables before with my own software with lots of success, for the most part they seem to do a good job replicating an rs232 serial port. I think the voltages are a little different and they are not exactly the same but for most applications they work fine.

I have heard that some adapters don't work and others do, I have used 3 different adapters and found all worked for my applications. I know two of them used the prolific driver and I would imagine the chip sets were the same, while the other used something else.

A related topic, and likely not that important to your question, a USB to parallel port adapter is a completly different story where you are mostly SOL.