Program called TrayApp is trying to install on my PC, Adobe keeps trying to download but never completes

TrayApp is an application that comes bundled with the HP Photosmart Digital Imaging software, and is used to scan and print documents and photos. It is included with the installation CDs of most HP products. A file called TrayApp.msi tells your PC how to install the required software and drivers.

Source: http://www.trayappmsi.com/ Be warned the fix on the site is "selling" a not to be used Registry Cleaner.

Try uninstalling and reinstalling.

If you have uninstalled use Auto runs to remove the Start Up item

To identify what loads when you boot use Autoruns (freeware from Microsoft).

http://www.microsoft.com/technet/sysinternals/ProcessesAndThreads/Autoruns.mspx

With Autoruns you can uncheck an item, which disables it from starting, or you can right click an item and then delete it. If you uncheck you can recheck to re-enable the item. It is a much safer approach than editing the Registry and better than using msconfig.

Another useful feature of the programme is that you can right click an item and select Search Online to get information about the item selected.