I found this ages ago to fix this same issue **FIXED**
Ok guys, found a fix. If anyone is having the same problems too, this will work for both XP and Vista, x32 and x64 if you're missing an options.ini file in My Documents for XP or User Name\Documents\ for Vista. If you're missing the options.ini file, do this and it will work!
Open your My Documents folder and add "options.ini" file (plain text file with renamed extension), then add the following and save the file:
AntiAliasing =
DrawScrollAnchor =
GameSpyIPAddress = 0.0.0.0
Gamma = 50
IPAddress = 0.0.0.0
IdealStaticGameLOD = High
LanguageFilter = false
MoveScrollAnchor =
MusicVolume = 55
Resolution = 800 600
Retaliation = yes
SFX3DVolume = 79
SFXVolume = 71
ScrollFactor = 50
SendDelay = no
StaticGameLOD = Low
UseAlternateMouse = no
UseDoubleClickAttackMove = no
VoiceVolume = 70
After that, re-enter the game and set options to your liking.
Hope it helps you