Well, first of all, you need to find the key that says CAPS LOCK on it and press that ONCE. If the little light on the keyboard turns off, don't worry, that's normal.
In other words:



Once you're done with that check out the following thread for possible solutions:

Panic Button

IMPULSE SHOWS DOWNLOAD SUCCESSFUL BUT GAME CANNOT LAUNCH. EVEN MY DISC WON'T LAUNCH. WORKED FINE ON MY DELL/XP LAPTOP INSTALLED A YEAR+ AGO. MESSAGE I GET WHEN DISC INSERTED:
EVENT: APPCRASH
APPLIC: GC2Launch.exe
AP VERSION: 0.0.0.0.
PLUS MORE DATA I CAN'T MAKE USE OF.
I DON'T KNOW WHAT THIS MEANS BUT WINDOWS/VISTAS ONLINE SEARCH CAME UP EMPTY.

I finally got the message on the caps lock. Maybe I have a learning disability.
As I am new to all of this, I am including the entire message from my Vistas message.
Event: APPCRASH
Application: GC2Launch.exe
Version: 0.0.0.0
Timestamp: 45804a84
Fault Module: DXAxHost.dll
Fault Mod Vers: 2.0.0.0
Fault Timestamp 44a44547
Exception Code: c0000005
Except. Offset: 000208e8
OS Version: 6.0.6001.2.1.0.768.3
Locale ID: 1033
Addtnl Info 1: 6776
Addtnl Info 2: c7ac7a4f369dbff87608da4358ffa744
Addtnl Info 3: ef1b
Addtnl Info 4: 00ce1dbf25dbd9e3d98a89d71d094306
Please let me know if I even have a clue. I am probably out of my league, but I am willing to try. Thank you for any help.

Seabass,
I un-installed DL & DA, turned off my firewall, re-installed thru impulse....it worked. Also was able to purchase & successfully download Twilight thru Stardock. Thanks for the help.