This is driving me to drink!!!!!

I'm trying to upgrade from XP HOME ->PRO and encountering a problem. First, after selecting to "upgrade" and entering the key, as expected, the machine reboots and i'm then met with a blue screen (something about "process1_initialization" failure - something like that - can't remember because I'm not home). I thought this was possibly related to my firewall, so I uninstalled the firewall. Now the Windows XP screen briefly appears then it goes blank. Constant "flickering" from the HD light, but nothing happening!

Do I have to blow everything off the machine and do a clean install or is there something else that can be done to make this work?

*pouring another drink until someone replies... LOL*

Thanks.