Internet Explorer proxy settings won't change - "some settings are managed by system adminsitrator"

Credit for this solution belongs here:

I came across a computer with a malware infection that had its Internet Explorer proxy settings configured, but I couldn't remove the proxy settings.  When I went to internet properties, it said "some settings are managed by system adminsitrator"

This computer was not part of a domain and had nothing set in local policies.  The fix was to change the value for ProxySettingsPerUser from 0 to 1 in the registry here:

HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\CurrentVersion\Internet Settings -> ProxySettingsPerUser

Computer replacement plan

I've often struggled with a hard and fast policy for replacing laptops in a business environment.  Some people swear by a 3 year rotation, some go up to 5 years.  Some use equipment until the old equipment wears out.  I've decided that this is what I'm going to recommend to my clients:

Laptops with conventional hard drives - replace after 3 years
Laptops with SSD hard drives - replace after 4 years
Desktops (aggressive) - replace after 4 years
Desktops (conservative) - replace after 5 years

This is as much about likelihood of failure as speed after a certain amount of time.