I'm not sure what you mean when you say you switched UAC from "Administrator" to "Standard".  Unless you disable UAC completely, it's always active for BOTH administrators and standard users; it's not one or the other.  By default, UAC prompts for administrators are just a Yes/No prompt and do NOT appear for built-in Windows functions, but you can switch it to prompt even for those built-in Windows functions and/or have the prompt require an actual password rather than just a Yes click for additional security.  Then for standard users, again by default, UAC prompts for administrative credentials (since standard users can't use their own account for elevation), or you can choose to have all elevation requests automatically denied.

But whatever you did, just click Start, type "User account control", and click the result that says "Change user account control settings".  The default mode is the second notch from the top.  If you're running Windows 10 Pro rather than Home, you can further customize a few behaviors related to UAC by going to Local Security Policy > Local Policies > Security Options, and scrolling down to the bottom for the User Account Control-related settings.

Ok, reading this a bit more carefully, did you mean to say that you accidentally switched your account from an administrator to a standard user?  If so, your account type has nothing to do with your User Account Control settings, although changing your account type will certainly change how UAC behaves for your account.  If that's what happened, do you have any other admin accounts created on the system?  If so, just log in as one of them, go to User Account Settings, and make that other account an administrator again.  If you don't have any other admin accounts, you will indeed need to boot into Safe Mode using one of the mechanisms I described (or you can find some others by Googling "Windows 10 boot Safe Mode"), then when you get into Safe Mode, open Command Prompt and enter "net user" to view the usernames of the local accounts, which don't always match display names. Note your account's username, then enter the command below, with two changes.  First, for some reason this post wouldn't get accepted until I added a space between "local" and "group", but that actually needs to be entered as one word, and second obviously substitute your own username:

net local group Administrators yourusername /add

In addition to the above, with respect to getting into Safe Mode, custom boot options work a bit differently on systems that boot in UEFI mode.  Microsoft removed the F8 key because modern PCs boot so quickly that they would have either had to expect users to press F8 in a ridiculously small window of time, or else introduce a delay on every single boot just to accommodate the few times someone wanted to perform a non-standard boot.  Neither would've been an ideal experience for users, so now the quick way to do it is to hold Shift while clicking Restart, which will bring up a menu where you can specify that the NEXT boot should be done in a different way.  Or you can run "msconfig" and select Safe Mode under the Boot tab.  And if you ever need to access Safe Mode because your system won't boot normally, Windows automatically switches to Automatic Startup Repair if Windows fails to load normally twice in a row, and you'll have the option to choose Safe Mode that way too.

From jphughan .. (Ok, reading this a bit more carefully, did you mean to say that you accidentally switched your account from an administrator to a standard user? .. ) yeah .. that's what I did .. will boot into safe mode and give it a try .. thank all of you for taking a look and for the help .. will be back on in the morning to let you all know if I was successful .. Thanks again .. take care ..