What I mean by reinstall is by using ftp://freepascal.dfmk.hu/pub/lazarus/snapshots/ to get a new snapshot. The latest seems to be Lazarus-1.1-41377-fpc-2.6.3-20130524-win64.exe. In order to use it I must first uninstall Lazarus. I've had to do this a few times.
Do you mean you have a snapshot installed, and you are running it, at the same time you test your SVN trunk version? Do you use the same config settings for both, or do you use --pcp parameter for separate configs?
Using a SubVersion client is an extremely easy task. Building Lazarus from the trunk repo is also an extremely easy task.
Apparently you have problems with both which means you are doing something fundamentally wrong. I am trying to figure out what that is.
You already got advice from others but here is some more:
1. Get rid of the snapshot installations. Then never install them again. Pretend they don't exist!
2. Make sure you have FPC installed. FPC 2.6.2 is preferred. Test it on a cmd line.
3. Delete your local Lazarus configuration if you doubt it is corrupted.
4. Revert any possible local changes in your SVN directory. See "Revert" in TortoiseSVN menu in file explorer, or do "svn revert -R ." on cmd line.
5. Update the latest Lazarus sources to your SVN directory.
6. Build with "make clean all".
7. Start from cmd line: "lazarus".
And why do you think I should know that Lazarus doesn't use the registry? Why would I even look to see as long as things are working properly? Now I know.
You have told yourself that things are NOT working properly. With configuration problems the fist question usually is: "Where is this data stored?".
I also don't see why you thing keeping FPC inside the Lazarus directory is odd. As long as the paths are set properly it can be anywhere. You should know this by now!
It is odd because it brings no benefits but it causes lots of problems.
You even noticed it yourself when you had to copy FPC directory again back to your Lazarus SVN directory, didn't you?
It also slows things down when TortoiseSVN is tracking files which can potentially be revisioned.
Typically only revisioned files, and files generated from those files, are kept in an SVN directory. If you add a file there, then you typically plan to add it under revision control later.