What about booting in Safe Mode and then running regedit or regedt32.
'Safe Mode' is a special mode you can start your computer in if you are having trouble.
As the computer is booting you need to press F8 (best success is achieved by repeatedly press it). This will display the Start-Up menu and one of the options will be Safe Mode.
Safe Mode is useful because it loads a minimum set of drivers to get the computer started and doesn't load any extra programs. Your display will be at 640x480 but it is useful for fixing driver problems as you can alter the set up without having to run it.
Another option is to run msconfig.exe
Start -> Run
then type msconfig into the box that appears. This runs a program that allows you to configure the computer startup
This has a lot of options but basically
General Tab: General Start-up options
Services Tab: Allows you to specify which services to load at start-up, this is for debug not general configuration.
Start-up Tab: Allows you to specify which programs will run when you start-up, again this is for debug not general configuration.
If you are having a problem at start-up this allows you to isolate the program/service causing the problem by excluding it temporarily. Once you have isolated the problem you can deal with it (uninstall the program causing the problem for instance).
For Task Manger like functionality (only better) you could download Process Explorer and you should just be able to run it like a normal program.
It's just a program to put on your computer if you wish.