Please see the following, I’m unable to go any further:
1]
A default installation will be on the C: drive not on another drive where the OS is.
Why are you trying to install on another drive?
2]
You don’t even have 2Gb(!) free on that drive, which means the drive is full.
Only the vps is already about 60Mb.
3]
You can’t just install the shields only, other things are also needed for avast to run.
As you can see at the first image you posted, they are components.
Meaning parts of avast.
You can’t build a entire car if you only have some parts for it 
The F drive is the system drive.
I’ve always installed just the shields. I’m using it in another PC this way and it works fine.
avast lets you deselect everything else, surely the rest must be optional.
It’s a small (14GB) XP partition, I have about 2GB spare.
No, there are still parts of avast that you do not see which must be installed for avast to work.
Two simple examples of them:
- The UI
- The updater part
Have you already removed all temporary files ?
I suggest to use CCleaner and Glary Utilities for that.
Each can find things the other can’t.
Defragmented the drive ?
Are you using the online or the offline installer ?
The UI and updater install as part of the base system what ever options you select.
Let me ask you something. I have a second HDD in the PC, has a much bigger NTFS partition.
I installed avast there and it seems to be working fine.
So now I have Windows XP on the first drive (drive F) and the avast for this system installed
on the second HDD (i:\program files\AVAST software\
Is this a supported configuration ?
It is not a default (usual) configuration, but it should work without a problem.