Windows Installer failure! PLEASE HELP!

Hi,
I seem to be having problems with Windows Installer.
Every time I try to install a program, this error message comes up:
📎poo.jpg
An example of when this has happened is when I'm trying to install the Microsoft Office 2010 Trial.
I've tried to troubleshoot it using 'Microsoft Fix It' but it made no difference.
Some sites told me to go into services.msc and check if the 'Windows Installer' service was running but the service itself wasn't even on the list!
I can't re-download and install it as the error comes up as I do so I'm in desperate need of help
PC Specs:

• HP m9265.uk
• Windows Vista Home Premium 32-bit (Service Pack 2)
• 3GB RAM
• 750GB HDD
• Intel Core 2 Quad CPU Q6600 @ 2.40GHz

Read here, see if it's any help: Error “The Windows Installer Service Could Not Be Accessed” when installing or updating programs on Windows 7 or Windows Vista

Thank you SO MUCH! It works

Excellent, glad that help. Thank you for letting me know.