ITunes wont install using update or manual download! HELP!

Question

having major problems with my iTunes. i currently have 16 videos trying to download and i keep getting error messages everytime. contacted iTunes support and they said i needed to update to the latest version of iTunes. When i then told them that it won't let me they suggested downloading onto a different system! hugely useful! the problem i am getting with updating iTunes is that if i use the Apple Update it comes up with an error saying "failed to install try downloading manually" so i do! download the installer files manually and then double click on it as usual. the installer check comes up and i click on run. then nothing happens! the run box dissapears but nothing installs and nothing else comes up in its place! highly annoying as you can imagine! anybody any ideas on how to fix this so i can finally watch my 16 shows!

Answer 1

the fix microsoft suggested didnt work. the windows installer comes up fine:
Windows ® Installer. V 3.01.4001.5512
msiexec /Option <Required Parameter> [Optional Parameter]
Install Options
</package | /i> <Product.msi>
Installs or configures a product
/a <Product.msi>
Administrative install - Installs a product on the network
/j<u|m> <Product.msi> [/t <Transform List>] [/g <Language ID>]
Advertises a product - m to all users, u to current user
</uninstall | /x> <Product.msi | ProductCode>
Uninstalls the product
Display Options
/quiet
Quiet mode, no user interaction
/passive
Unattended mode - progress bar only
/q[n|b|r|f]
Sets user interface level
n - No UI
b - Basic UI
r - Reduced UI
f - Full UI (default)
/help
Help information
Restart Options
/norestart
Do not restart after the installation is complete
/promptrestart
Prompts the user for restart if necessary
/forcerestart
Always restart the computer after installation
Logging Options
/l[i|w|e|a|r|u|c|m|o|p|v|x|+|!|*] <LogFile>
i - Status messages
w - Nonfatal warnings
e - All error messages
a - Start up of actions
r - Action-specific records
u - User requests
c - Initial UI parameters
m - Out-of-memory or fatal exit information
o - Out-of-disk-space messages
p - Terminal properties
v - Verbose output
x - Extra debugging information
+ - Append to existing log file
! - Flush each line to the log
* - Log all information, except for v and x options
/log <LogFile>
Equivalent of /l* <LogFile>
Update Options
/update <Update1.msp>[;Update2.msp]
Applies update(s)
/uninstall <PatchCodeGuid>[;Update2.msp] /package <Product.msi | ProductCode>
Remove update(s) for a product
Repair Options
/f[p|e|c|m|s|o|d|a|u|v] <Product.msi | ProductCode>
Repairs a product
p - only if file is missing
o - if file is missing or an older version is installed (default)
e - if file is missing or an equal or older version is installed
d - if file is missing or a different version is installed
c - if file is missing or checksum does not match the calculated value
a - forces all files to be reinstalled
u - all required user-specific registry entries (default)
m - all required computer-specific registry entries (default)
s - all existing shortcuts (default)
v - runs from source and recaches local package
Setting Public Properties
[PROPERTY=PropertyValue]
Consult the Windows ® Installer SDK for additional documentation on the
command line syntax.
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Portions of this software are based in part on the work of the Independent JPEG Group.