怎樣釋放磁碟空間

我的電腦內有太多程式不知可否delete. 請各位有料之仕指點本人哪些可delete及它們有何用途,謝謝.
Adobe PDF IFilter 6.0 (19.68MB)
Adobe Reader 7.1.0-Chinese Traditional (87.32MB)
Apple Software Update (2.4MB)
Arc Soft Photo Studio 5.5 (25.28MB)
Crystal Maze from Compaq (5.73MB)
InterVideo Win DVD Creator 2 (60MB)
KBD (7.92MB)
Microsoft office Professional Edition 2003 (454MB)
Norton Security Scan (9.39MB)
Presario PC Help (4.71MB)
Python 2.2 combined win 32 extensions (22.71MB)
Python 2.2.1 (22.71MB)
Winamp Toolbar for internet explorer (2.09MB)
Window Internet Explarer 7 (6.3MB)
Windows Internet Live Toolbar (6.49MB)
Windows Internet Liver 上載工具 (.22MB)
Windows Internet Live 登入小幫手 (1.94MB)
Wiseman Voice Engine (58.78MB)
Windows Internet Live 程式集 (34.38MB)
Word Symphony form Compaq (3.68MB)
Yahoo!Install Manager (3.51MB)
Yahoo! 工具列 (3.51MB)
另外請問我現用avast,那麼norton security scan是否可以delete?
Microsoft office Professional 2003 我只用其中2-3個software,可否捒選不全部安裝?