Neil,
Tks for the tip.
Upon further investigation, I noticed the following:-
I rebooted the PC and went into the CMOS and reset the serial port detection (changing the option from auto to COM1 and vice-versa) and then rebooted the PC again.
If I use a new form that contain only 2 buttons and the OLE control, I can open and close the port without problems.
Then I run the application and plug in the weighbridge, I was able to run it without problems mentioned earlier. After exiting the system, I rebooted the PC and this is when the problem begins, now both methods of accessing the COM port failed with hyperterminal also giving me a message "Port in use by another program". I checked thru the service logs and couldn't identify anything in particular.
Could this be a problem where :-
1) My application did not close the port correctly upon exiting ( currently I set portopen=.f. in the destroy event of the form , could it be that I need to close someother things upon exiting).
2) Windows XP is keeping the OCX running in the background?

In repeating the CMOS reset and rebooting process, I noticed that if I just use the 2 button form to open and close ports and reboot, I can use the second time round with no problems. But if I use the application and plug in the weighbridge, I can use it the first time but not the second time (after rebooting without going into the CMOS to reset)

Is there a way for me to identify specifically what is holding on to the port?
Thanks
Yau