Error C0150004 - can't update

Hello, I'm new here. My name is Florencia, I ended up here while searching for a solution to some errors with Windows Update.

Since I bought this notebook (with Vista Home Basic 32bit) I've been having various erros with WU. First, everytime a new update was available it showed error 80240016, saying there were other updates going on. Sometimes it would download the updates succesfully but when it rebooted to install the updates, it would freeze in the screen "installing update 1 of x". I searched for months for solutions for these problems, I contacted Microsoft via mail and via chat but they gave me no solution.
Finally, last night I found these forums and searched here for a solution. I tried the methods explained here:
http://www.vistax64.com/software-tools/183498-windows-update-reset-repair-tools.html
Now the previous error (80240016) doesn't show up anymore when I try to look for new updates. BUT (there's always a but) instead I have a new error: C0150004, Windows could't find new updates.
I'm not an expert with these things so I would really appreaciate if anyone could help me a little bit with this. I'm seriously fed up with this problem and would love to find a solution.

I apologise for errors in my spelling or grammar since English is not my first language, I hope you could understand my explanation.
Thank you.

Go to C:\Windows\WinSxS and check do you have there pending.xml.If this file exist take ownership of this file http://www.vistax64.com/tutorials/67717-take-ownership-file.html
and remove it+restart

I couldn't find that file. There's a file in the folder C:\Windows\WinSxS\Temp\PendingRenames which is:
20704426bb66c801e1000000840a7009.pending
I guess it's not the same, but just in case it matters.