<<Is there anyway that I can find out if I deleted some registry that I shouldn't have?>>
Not really, although "registry cleaner" programs seem to have purchasers/users thinking so. The registry changes all the time, based on what is installed/filed...I know of nothing that can tell a user accurately what should be...where it is not. Registry cleaners are devised for users who don't understand what it is that they think they want...don't understand the complexity of Windows...don't understand what the registry is.Bleeping Computer does not recommend the use of such programs, for various reasons.
Demystifying the Windows Registry - http://www.bleepingcomputer.com/tutorials/demystifying-the-windows-registry/#backup
Windows Registry - Wikipedia, the free encyclopedia - http://en.wikipedia.org/wiki/Windows_Registry
Windows registry information for advanced users - http://support.microsoft.com/kb/256986
If registry errors don't result in catastrophic effects, I would suggest not thinking about them. When errors produce error messages, that's the time to worry about possibly making adjustments to the registry.
IMO, if you suspect that you have deleted necessary registry entries...best thing to do would be a repair install of XP.
<<I want to upgrade my computer from 3GB of ram to 4GB but I have a 32bit Vista OS and I read that 3GB is the most a 32bit OS will handle, is that true?>>
No...well, partially true
4GB is the routine max for a 32-bit O/S.Memory Limits, Windows
Edited by hamluis, 06 November 2010 - 12:46 PM.