Windows 7: dot net framework 3.5 setup error on windows 7? how to install?

dear sevenforums community,

i am using win 7 home premium 64 bit.
yesterday, i bought a new 3.5 external hard drive, inside it there is a dot net framework 3.5 installation package.
Not knowing that win 7 SP 1 comes from net framework 3.5 installed already, i double clicked the exe file from the external hdd.



and then i encountered the PCA (program compatibility assistant) notification, this program does not installed correctly thingy.

from there, i google and try to redo it from scratch, by which i mean i tried to uninstall the 3.5 framework from my Windows 7.
and then i unistall it with .net fx cleanup tool from the msdn blog (http://blogs.msdn.com/cfs-filesystem..._5F00_tool.zip).

Now, i am trying to re-install the net framework 3.5 from the 231 mb full package net framework 3.5 i got from microsoft web.

now, this is the problem i encountered, when i tried to install it, i got "setup.exe stop working" or something like that,
below is the error report attached on 3 files.





My question simply is, how to re-install dot net framework 3.5 SP 1 on my Win 7 now that i had uninstall it due to my own stupidity?


thank you very much and have a great day,


kungfupanda

Since .net framework 3.5 is included as part of Windows 7 I'd try to roll back my computer by using a restore point from a date/time prior to when the problems first appeared.

System Restore

If that doesn't work try repairing those sytem files by running a system file checker scan from an elevated command prompt (option two.) You already know the .net framework files are damaged or corrupted so the SFC scan should definitely indicate that problems were found. Run the scan 3 times and reboot the computer after each scan.

SFC /SCANNOW Command - System File Checker

If SFC is unable to restore the .net framework files then option three shows how to generate a cbs.log and figure out what files could not be repaired. Once you get that information you could manually extract and install clean copies of those files from a Windows 7 installation disk.

Extract Files from Windows 7 Installation DVD

Personally, if running SFC three times didn't fix the problem I'd just go straight to a Repair Install.

Repair Install