I am running XP (home) SP2 fully patched.
I have just had a situation when I wanted to remove an application and used Control Panel, Add/Remove Programs.
It gave the 'waiting for the list to be populated' message and then just stayed blank for nearly 30 minutes.
I have deleted three programs using their Uninstall entries in their All Programs entry, and the list is now being populated.
Is there some limit to just how many entries the Add/Remove applet can handle, or is there some way it can be made to handle more?

Yes, I know I have a lot of entries (i.e. programs) but I don't want to have to delete some in order to install others. I thought we were past things like that?

This is likely to be some other problem.
Run defrag and chkdsk.
Check for adequate disk space.
Check Event viewer as well-look for disk errors.

i use ccleaner's tool option to remove program and it works for me. it may also work for you .www.ccleaner.com

I have ccleaner - never thought to use it for that!
I just defragged the c: drive - hardly did anything. Interesting chkdsk doesn't appear to run on c: drive, it hangs (or at least is taking a VERY long time at stage 2 - indices).
So where is add/remove getting the program list if ccleaner can pick it up?

Is it still running? Did it complete?
Check event viewer/System and check for adequate disk space.
I assume CC uses the registry.