Vista - Program installation

Ihave couple problem, please help. First, on my laptop, on partition C have left 7.5 GB out of 29.2. And I didnt install any programs there, so I am afraid I will run out with more updates.Second, I had installed the Adobe Photoshop CS3, and accidentally it was partially on C and D. So since I wanted all to be on D, I run uninstaller and then deleted all Adobe Photoshop files from both partitions and from registry. Now, when I trying to re install the photoshop, i click on the setup,all it does, it comes to the point that say Adobe photoshop installer, windows confirms that I allow to proceed, and then its ends, no continuation. I tried to run as administrator, by pressing right click on the setup file, doesnt make any difference.
Where is the problem?

Thanks

See the following:

Disk Cleanup - Correct Shortcut for Vista 64 bit

Disk Cleanup

Temporary Files - Temp Folder

For some deeper cleaning, see Extended Disk Cleanup

Also see SP1 Disk Cleanup Tool

Finally, this may help you move forward in cleaning regularly - Disk Cleanup - Last Access Limit on Temp Files