Sky on pc

When I first originally downloaded and installed Steam, almost only half of the time it would open. Now after updating it, the program never starts up, just immediately goes unresponsive, I don't know what i've done? I bought the game in Europe but use it in the middle east, but that hasn't to do with launching it?

These are my PC specs:

perating System: Windows Vista™ Home Premium (6.0, Build 6000) (6000.vista_gdr.100218-0019)
Language: English (Regional Setting: English)
System Manufacturer: Dell Inc.
System Model: XPS M1330
BIOS: Phoenix ROM BIOS PLUS Version 1.10 A15
Processor: Intel(R) Core(TM)2 Duo CPU T7300 @ 2.00GHz (2 CPUs), ~2.0GHz
Memory: 2046MB RAM
Page File: 1183MB used, 3128MB available
Windows Dir: C:\Windows