[Diy_efi] OBD II cable "

[MATOSINHO]

This is the first time I write to the diy-efi forum asking for help. As 
my english is far from brilliant and I am not an skilfull engineer 
(only studying my second course) I had decided to make one of the OBDII 
scan that "scan-tool" sells. Unfortunately it didn't work but I didn't 
care because everything was OK with my '03 VW Golf. For some reason she 
started to fail when starting, a couple of weeks ago and there is a 
funny array in the on-board computer.
 So my question is is there any downloadable (free or very cheap if 
possible) that allows me to read the error codes using an OBD II cable 
connected directly to my personal laptop???.

I would be very gratefur if any help was be recieved.