OK to delete Windows Update Setup Files?

Oh, I know the answers probably somewhere on this board, but there comes a point in time when searching through umpteen million posts is just too difficult. So, here's what I need to know:

CAN THE FILES IN THE FOLDERS BELOW BE DELETED?

Windows 98SE

C:\Windows\Windows Update Setup Files
Bunch of .cab files and some .exe files

C:\Windows\Downloaded Program Files
A lot of ActiveX control (alpha-numeric) files, a Shockwave, Hotmail and some other files.

C:\Windows\Cache
Two folders: Adobe Reader 6.0; Adobe Reader 6.0.1
(I'm using 6.01 with 6.02 update

C:\Program Files\Uninstall Information

Thanks very much,

Starkman