I recently bought new HP computer with Windows 7. I loaded my Adobe Creative Suite 2 Premium. Illustrator tries to open then just disappears. I can not open PDF's. Get the following message: This program doesn't have valid digital signature that verifies it's signature. No valid Acrobat S/N found. Acrobat will now quit. Then: There is a problem with Adobe Acrobat/Reader. Please exit and try again. When I exit - computer locks up.