I reinstalled SendBlaster after formatting my Hard Disk. The license key is not accepted (the OK button is grayed)

Probably you installed SendBlaster 2 after formatting, but the license key you purchesed is valid on SendBlaster version 1 only.

The licence key of version 1 will not work on SendBlaster 2.

If you bought Sendblaster after July 1 2009 you are elegible to get a FREE upgrade to SendBlaster 2 Pro: http://www.sendblaster.com/freeupgrade/upgrade.htm

Otherwise you may:

1) Continue using SendBlaster 1. You can download it here: http://download.sendblaster.com/sendblaster163.zip

2) Buy the upgrade to version 2 here:
http://www.sendblaster.com/shop/?products=UP1X20

I reinstalled my office computer and because of that also reinstalled my copy of SendBlaster Pro. Now I can't upgrade the "Free Edition" to a "Pro". Please help!

You probably registered your copy of SendBlaster and now you're entering the registration code instead of the license key.