Hi everyone,
A few days ago, I tried to programm a picaxe microcontroller via the serial cable on my windows 7 PC but it gave an error like 'no hardware found on comm port4 ' or the same with 'comm port3' etc.. when I changed the serial port settings in programming editor software. If you are facing the same problem then this may be the possible solution (well it worked in my case).
Actually win 7, which is the newer version of windows don't recognize serial port (which is old in this USB generation) on its own and the port even if it exists on your computer, remains disabled. Hence the same needs to be done manually and I found some very usefull topics on the internet. Most of them were very complex but I found this https://forums.virtualbox.org/viewtopic.php?f=6&t=26860 which worked perfectly. Just follow the procedure for win 7 as shown in the link and you will be able to use the serial port.
Thank you