Yes it can be done
http://www.instructables.com/id/Control-real-world-devices-with-your-PC/
Lots of tricks. Like as technical says, you only have one com port so you have to remember whether it is hyperterm using it or the download program. Almost worth having two PCs while you debug it.
You have to get the N or T right. You have to get the circuit right on your particular picaxe input pin - replicate the 10k/22k circuit on another pin, or use a max232 (but watch the inversion). Output can be directly from another pin to the PC.
If it can talk to vb.net it can talk to hyperterminal.
vt100 doesn't matter - vt100 just adds commands so the cursor can move around the screen (useful when you are running wordstar on a remote board).
Do it in stages. Hyperterminal at 2400 baud, 8 bits, 1 stop bit, no parity and flow control=none.
Simple loopback device - a D9 pin with pins 2 and 3 joined. I have used mine many times.
Hyperterminal, single character to a picaxe, and get the picaxe to light a led when it gets that character.
Watch which port hyperterminal defaults to. Mine defaults to com2 and it needs to use com1. I saved that as a session, then went and found the little .ht setup file, and put a shortcut to that on the desktop. Now hyperterminal starts with all the settings as they should be.
Then new code, picaxe sends a single character every second and see if it appears on hyperterminal.
Try at 2400 first, then raise the baud rate later.
Absolute simplest serin code will be:
serin 3,N2400,b0
Absolute simplest serout code will be:
serout 0,N2400,(b0)
Pins don't really matter. I used 3 for input and 0 for output on an 08M.
And that is deliberately going to pin0, because this is the same pin as the feedback pin from the picaxe to the picaxe program editor - but you would never need to worry about that because the picaxe editor is shut down and you are now using hyperterminal instead. Right? (I made that mistake about 20x when writing that instructable *grin*)