从昨天开始L4D出现错误，无法联机，紧急求助！T_T

迷宫

进入游戏我就感觉异常，因为游戏一顿一顿的（在菜单界面就这样）甚至卡死 我只好重启 重启后正常联机。后来我晚上又联机。结果刷出服务器，点进入，读取进度条时候 进度条只走一点点就卡住不动，等一会没反应，后来弹出 提示已断线，下面提示一行英文，大概意思是失败10次（failed ……10……）看控制台里 发送了10次数据 没成功。
今天早上我再试还是如此，再次进入游戏，直接呼出控制台，发现如下提示，希望高人告诉我什么原因？
S_StartSound: Failed to load sound '*#musicl4d2l4d2_c1_pc.mp3', file probably missing from disk/repository
BinkOpen( d:games paradiseleft 4 dead 2left4dead2medial4d2_background01.bik )
Can't use cheat cvar fog_start in multiplayer, unless the server has sv_cheats set to 1.
Can't use cheat cvar fog_end in multiplayer, unless the server has sv_cheats set to 1.
Can't use cheat cvar fog_color in multiplayer, unless the server has sv_cheats set to 1.
Can't use cheat cvar fog_colorskybox in multiplayer, unless the server has sv_cheats set to 1.
Can't use cheat cvar fog_color in multiplayer, unless the server has sv_cheats set to 1.
Can't use cheat cvar fog_colorskybox in multiplayer, unless the server has sv_cheats set to 1.

PS：学校上课用VS2005，课程学完 我就删了，我自己怀疑是不是卸载2005时候顺带把VC运行库文件也卸载了？
但是我是前两天卸载的 为什么玩了两天才出问题了。搞不清楚了。。