Ensure that the date, time and time zone is correct. Follow the steps below to verify: Click on time on bottom right corner. Click Change date and time settings. Select Change Time Zone and verify. Activate Office and check for results.
If the issue still persists, then restart computer in Windows clean boot following the steps from the KB below to install Office 2010: Note: Ensure you restart the computer in normal mode after troubleshooting. I hope something in there will help you. Or hopefully another forums member will have advice for you. Maybe a problem with the installation not activation. When I first started with Mint, it was 17.3 and installing word/excel 2007 was a breeze. Then I upgraded to 18 and completely rebuilt the laptop (well it was a different laptop). I had no end of trouble trying to install word and excel.
The following are the notes I wrote at the time (in case I have to do it again). They may be relevant if your 2010 copy of office is a 32 bit version and you are installing on a 64 bit machine. Office 2007 Setup 12.
Install wine from software manager. If Office 2007 is installed with either winetricks or playonlinux or directly from wine it will not work. This is because wine gets something wrong with office (32 bit app) in a 64 bit mint installation. Instead from a terminal enter.
Code: andy@T430 ~ $ WINEARCH=win32 WINEPREFIX=~/.win32 winecfg wine: created the configuration directory '/home/andy/.win32' fixme:urlmon:DownloadBSC_OnProgress Unsupported status 3 fixme:wininet:InternetLockRequestFile STUB fixme:storage:create_storagefile Storage share mode not implemented. Err:mscoree:LoadLibraryShim error reading registry key for installroot err:mscoree:LoadLibraryShim error reading registry key for installroot err:mscoree:LoadLibraryShim error reading registry key for installroot err:mscoree:LoadLibraryShim error reading registry key for installroot fixme:urlmon:DownloadBSC_OnProgress Unsupported status 3 fixme:wininet:InternetLockRequestFile STUB fixme:storage:create_storagefile Storage share mode not implemented. Err:winediag:SECUR32_initNTLMSP ntlm_auth was not found or is outdated. Make sure that ntlm_auth>= 3.0.25 is in your path. Usually, you can find it in the winbind package of your distribution. Fixme:iphlpapi:NotifyAddrChange (Handle 0x11fe8a0, overlapped 0x11fe8ac): stub wine: configuration in '/home/andy/.win32' has been updated.