I've recently solved the issue of removing the 'Get Windows 10' to upgrade on Windows 7. However for a two year period I was unable to get windows updates. During that time I am concerned that I may have been infected with a rootkit and I'm wondering what is the best way to go about checking for and removing. Sophos and Kaspersky are two recommended removal tools that I've come across. Any advice or suggestions? Thanks. Brian

Malwarebytes. But... You have to go to Settings and then to the Protection tab and turn on "Scan for rootkits" in the Scan Options section.

Another scanner that I use when I encounter something that is tough to remove is Norton Power Eraser.

Please tell us why the specific concern about rootkits. Is it because of something you read on the internet or because your computer is behaving strangely?

I've run Malwarebytes a few times as suggested and thankfully nothing has been detected. So am I right to assume there is nothing there?
My reason for wanting to detect for rootkits was a concern that after this two year period of not receiving updates that my computer lacked the protection against hackers.
Thanks again for your help.

(IMO)

Assuming you feel sufficiently protected, that you haven't had anything "odd" occur - & even though you hadn't been getting updates, I wouldn't be particularly concerned.

I went a long time, in Win7, without updates (due to MS's purposeful stifling of Win7 updates, IOW taking AGES to update, seemly as a means to "promote" Win10), that I simply disabled updates altogether.

Likewise, I continue to use an XP system (gasp) that what, could it be 2 years now since MS last put out an update (that is without a hack, & with 1 exception).