First off to avoid any confusion between machines, unless peterm feels otherwise, lets stick to fixing one computer in this topic, and start another topic for each of your other machines (the air mattress fix can stay here though.......lol).
I have 7 folders, all users, all users.windows, default user, default user.windows, gail, gailc, gailee.
is it safe to delete the .windows, gail and gailc?
Yes, those were created by re-installing Windows. The ones currently in use should be the ones with the period in their name; users.windows, default user.windows
Having gail, gailc, gailee seems a bit strange (there should only be two), but gailee should be the current profile. A simple test would be to save something to My Documents and check which profile path it went into.
To check the All Users profile, right click the Start button and select Open All Users. Save a document there. See which All Users profile it was saved in, then delete it (the document).
You should be safe to delete the profile folders not in use. Make sure there's nothing you want from the gail and gailc profiles first, eg; documents, favorites, etc.
The error codes you are getting can be caused by ANY malfunctioning hardware, and you mentioned device manager showing a problem with the sound card. I know you're reluctant to go there, but we need to get all hardware issues resolved, so I suggest checking for updated drivers. Once you have those, uninstall those previously mentioned problem devices and reboot. Windows should find them on startup and re-install.
Is there anything else showing problems in Device Manager?
You have verified that the Quickbooks cd is OK by installing it on another system, but that doesn't rule out a possible problem with this comp's cd drive. Do you by chance have a cd drive cleaner disc? Compressed air available to blow out the drive? You might also want to try copying the disc to a folder of it's own on your harddrive, then run setup from there. If proper installation still fails, before brute force removing all related intuit/quickbook items with reg cleaners, etc, use Add/Remove programs ONLY
to uninstall it, then download the Windows Installer Cleanup Utility from Microsoft.http://support.micro...kb;en-us;290301
Run the tool and see if there's anything listed for Quickbooks/Intuit. If so, select it and click Remove. Should you notice any entries for any other uninstalled programs, remove them as well.
Remove any files/folders associated with Quickbooks and try installing again.