I have had this issue since I bought the machine a year ago. It has occurred intermittently from the very first fresh install of Windows 10 (without connecting to the internet), so almost certain it's not due to malware but more likely a driver/hardware issue.

4/5 times when my PC restarts, it gets as far as the Windows desktop but then hangs:
- the mouse cursor moves
- right clicking brings up the popup menu, but it's half-transparent and non-functional
- some of the task bar icons appear but not all
- the system is unusable: applications can't be started/used
- the start menu doesn't work

My solution until now has been to restart until finally this doesn't happen and from then on the system works fine. However, I try to avoid restarting the machine as much as possible due to this annoyance, so would really like to fix it.

Here are relevant log extracts from a couple of failed boot attempts where the freeze occurred:
- Application event log
- System event log
- ntbtlog.txt

The main recurrent system log error seems to be:

Log Name: System
Source: Microsoft-Windows-DistributedCOM
Date: 01/06/2016 08:42:31
Event ID: 10005
Task Category: None
Level: Error
Keywords: Classic
Computer: Dave-New-PC
DCOM got error "1084" attempting to start the service TermService with arguments "Unavailable" in order to run the server:
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<Provider Name="Microsoft-Windows-DistributedCOM" Guid="{1B562E86-B7AA-4131-BADC-B6F3A001407E}" EventSourceName="DCOM" />
<EventID Qualifiers="0">10005</EventID>
<TimeCreated SystemTime="2016-06-01T07:42:31.687410800Z" />
<Correlation />
<Execution ProcessID="756" ThreadID="920" />
<Security UserID="S-1-5-18" />
<Data Name="param1">1084</Data>
<Data Name="param2">TermService</Data>
<Data Name="param3">Unavailable</Data>
<Data Name="param4">{F9A874B6-F8A8-4D73-B5A8-AB610816828B}</Data>

If any more info is required to diagnose this, please let me know.

Thanks in advance.