xp sp2 系统下的nsis error问题

电脑不知道怎么了，下载的QQ，跑跑卡丁车都不能安装（ie保存，网际快车，讯雷都试了。都是在官网上下载的。单线程也试过了）。重新装了好几次系统，也格了c盘，也用卡巴斯基和木马杀客查了都没有发现病毒！但是还是无法解决nsis error错误！快疯掉了！

NSIS Error
---------------------------
The installer you are trying to use is corrupted or incomplete.
This could be the result of a damaged disk, a failed download or a virus.

You may want to contact the author of this installer to obtain a new copy.

It may be possible to skip this check using the /NCRC command line switch
(NOT RECOMMENDED).


以上是系统出现的对话框

各位高手帮帮我吧！！！！！！！！！！谢谢大家了！！！！！！！！