我原先安装的是STEP7V5.3SP2专业版(英文版).最近用V5.3SP3基本版(英文版)复盖其中的SP2基本版后,就发现,再重复安装SP3时就出错,要求重起WINDOWS(XPSP2).现想装SP3中文版也不能装.想卸掉原来版本也不成,出现"There are data on your computer which will be deleted the next time you restart the computer. This may lead to problems if you reinstall the softerware. Restart Windows and then start Setup again.