Recent issue play GunZ

[Awalltraqx]

Just 2 days ago, I cleaned out the inside of my tower, used a compressed air can, was careful, and sprayed smoothly. My monitor since then continues to go to sleep once I'm about to log into the server, goes black and then to sleep.
It only occurs in this game, have reinstalled, scanned for viruses, none. Everything else works fine, other games as well, only occurs when I try to play GunZ, I don't believe it's a graphics card issue because of it's requirements to play are so low

Minimum Requirements |Recommended Requirements
OS Windows XP, Windows Vista, Windows 7
Direct X | DirectX 9.0c or above
CPU Pentium III 500 MHz | Pentium III 800 MHz or higher
RAM 256 MB | 512 MB or above
Graphics Card Direct 3D 9.0 Compatible (Riva TNT) | GeForce 4MX or higher
Sound Card | Direct3D Sound Compatible
Mouse Windows Compatible (Wheel Mouse recommended)

Windows XP
ATI Radeon XPRESS 200 series
2.2GHZ~
1470MB RAM
Hp Pavillion 061
AMD Athlon 64
300GB HD
Board: MSI ALBACORE 1.0
Bus Clock: 200 megahertz
BIOS: Phoenix Technologies, LTD 3.47 03/03/2006