can't install/update .net and live messenger

hello,

i've recently re-installed windows XP home 32bit (original , OEM) from
scratch , and it seemed everything worked well, till i tried to run windows
live messenger. i got an error while installing it, and i went back to the
windows update website, and found out that i also have 2 more items there
that belong to .net framework that cannot be installed.
when trying to update them using windows update, i get an error window that
shows the items that cannot be installed:
Update to .NET Framework 3.5 Service Pack 1 for the .NET Framework Assistant
1.0 x86 (KB963707)
Microsoft .NET Framework 2.0 Service Pack 2 Security Update for Windows
2000, Windows Server 2003, and Windows XP (KB974417)

the error codes are 0x645 and 0x8007064C for .net, and 0x8007000d for
windows live messenger .
i also noticed that any program that uses .net framework cannot run.
i tried a lot of things but nothing helped. this includes :system restore,
uninstalling and then re-installing of .net and everything related to windows
live essentials , trying to install in safe mode (with network) , using the
windows cleanup tool ,using the tool of Aaron Stebner's to remove all traces
of .net framework , and even installing verion 4 of .net framework .

the windows live messenger problem is quite new to me. the .net problem
isn't.i had this problem for a long time till i decided to start everything
from scratch.

please help me. i really don't want to re-install windows again. i did this
thing for too many times that i almost remember the serial number by myself.

ok, i have no idea how it was fixed. i tried to uninstall all of those
components again, did some manual and automatic file and registry cleaning,
and windows update offered me to install everything again, and it updated
fine.

hopefully, this situation will hold till i get a new OS (maybe windows 7).