Windows Update / Clean Boot Problem

I'm not sure when Microsoft stopped updating Vista, but I have a Toshiba Satellite A305 running 64 bit Vista Home Premium. When I go into Windows Update it tells me that the most recent check for updates was on 03/14/17 and updates were installed on 06/23/17. When I click on 'check for updates' a very small box immediately pops up over the update icon in the right of the task bar. The box, which reads Windows can't check for updates immediately goes away while the system checks for updates.

It never stops checking for updates. and taskmgr shows that svchost begins consuming memory till it's over 1GB. If it really can't check for updates because there are no Microsoft updates available, shouldn't the system tell me that? Instead of just sying Checking for updates for hour upon hour?

I ran the system file checker which found some items but was unable to correct them all. Attempting a Windows update afterward changed nothing.

I tried to set up the laptop for a clean boot, but when I check Selective Startup and uncheck Load startup items it immediately fills in that box when I click apply. Likewise, when I go into Services, hide Microsoft services and click disable all, the system immediately re-puts check marks into two Avast services. So I seem to be unable to set this up for a clean boot.

All this may be a moot point if there are no more applicable updates for Vista, but I wanted to make sure.