If you can't sign in to your Outlook.com, Hotmail, Live, or MSN email account, or you're not sure how to sign in or sign out, here are some solutions.

Fix your audio drivers. Hardware problems can be caused by outdated or malfunctioning drivers. Make sure your audio driver is up to date and update it if needed. If that doesn't work, try uninstalling the audio driver (it will reinstall automatically).

If your system is asking you for your BitLocker recovery key, the following information may help you locate your recovery key and understand why you're being asked to provide it. Important: Microsoft support is unable to provide, or recreate, a lost BitLocker recovery key.

Sign in to SharePoint. SharePoint is a browser-based app that you connect to through your web browser, like so: Go to office.com, and sign in to your work or school account. In the upper left corner of the window, select the app launcher > All apps > SharePoint.

Check for Windows updates. Learn how to update drivers in Windows using Device Manager to update or reinstall a driver.

Earn points toward rewards by doing the stuff you do every day. It’s easy and it’s free. All you need to do is sign up, and Microsoft Rewards will be included in your Microsoft account: Microsoft Rewards. Once you’ve signed up, sign in to your Microsoft account to see your current points.

Your Hotmail or Outlook.com password is the same as your Microsoft Account password. If you can you sign in but are having problems with Outlook.com, check the service status. If the status isn't green, wait until the service is running normally and try again.

Learn how to get Microsoft account help, troubleshoot sign in issues, keep your account secure, and manage your Microsoft account dashboard.

You can download free, pre-built document templates with useful and creative themes from Office when you click File > New in your Office app. Templates can include calendars, business cards, letters, cards, brochures, newsletters, resumes, cover letters , presentations, social media and much more.

The VLOOKUP and HLOOKUP functions, together with INDEX and MATCH,  are some of the most useful functions in Excel. Note: The Lookup Wizard feature is no longer available in Excel. Here's an example of how to use VLOOKUP. =VLOOKUP (B2,C2:E7,3,TRUE) In this example, B2 is the first argument —an element of data that the function needs to work.