Vista - Can't Seem to Update...

I am currently running Microsoft Windows Vista Home Premium.
Until a couple of months ago my laptop seem to update fine, but now I have a total of 24 important updates. But when click update it downloads them and then starts installing them.
Sometimes it only gets to about 4% on update one and then won't update anymore...even if I leave it for a whole day. I've tried lots of different things and have try to install them manually from the microsoft website.
When I do this the update I am installing gets to around 99% and then nothing else seems to happen! Its very frustrating when it gets to 99% and then ..nothing!

Anyone's help would be greatly appreciated
Thanks
Lizi

Try this->How do I reset Windows Update components? and this->Description of the System Update Readiness Tool for Windows Vista, for Windows Server 2008, for Windows Server 2008 R2 Release Candidate, and for Windows 7 Release Candidate
and this->An update is available to fix a Background Intelligent Transfer Service (BITS) crash on a Windows Vista-based computer

If still nothing help try disable non -system service (How to perform a clean boot procedure to determine whether background programs are interfering with a game or a program that you currently use
) and again try install updates
if still nothing help try to reinstall Windows Installer ->Windows Installer 4.5 is available

geez louise Flavius,
I love all the info you give.
I read alot too