I uninstalled MC 6.0 and insatlled 6.5.2 but didnt have an activation code. I think i should have de-activated my licesne before trying to activate it again. I dont know what to do and how to go thru th eprocess... anyone have any quick fixes? 

1) For now run in trial mode.

2) On Monday, call Avid Support @ (800) 800-2843, option 2.  This is a free call. They can deactivate your v6 license.

Cowen:

If this is an emergency and you need immediate help, send an email to Avid Customer Advocate Marianna and include your system ID and current activation code, but don't post them here or on any other public website. If it's not an emergency, please follow Randall's instructions. Also, be advised that 6.0 to 6.5 is a paid upgrade. If you have not purchased the 6.5 upgrade, you can download and install the latest patch for 6.0, which is 6.0.3.4 to get all the latest fixes. If you're on a Mac, that requires a full uninstall of the current version and a "full install" of the 6.0.3.4 patch file. If you're on a PC, just download the 6.0.3.4 patch and add it on to 6.0. If you already have an older patch for 6.0 installed, you must remove that first before installing the 6.0.3.4 patch file.

Standing by waiting for your email
Marianna