Apple software problems - VISTA crashes?

Hi there!

I have a problem - I have apple qt installed on my pc laptop (Vista 32-bit) and I need to instal iTunes. I know it should be straightforward, but when I try to instal it it simply freezes at some point and no matter how long you wait it just doesn't go futher. I cannot cancel it coz the pc stops responding however the installation bar flashes as usual.

I had an idea that if I uninstal QT I will be able to load all software from the begging but uninstallation just freezes as well.

Is there any way of getting rid of it manually? Like deleting the files and cleaning up the registry?

I haven't been doing any updates for some time.

Please let me know what to do ASAP...