Question : Network PC user unable to install applications on own PC without being logged in as Administrator

A client has a problem with 1 PC client on an SBS network.  They want the user to be able to install some basic applications , such as installing a screensave application on their PC, when logged in on the local Domain. All other PCs can do this. When this use tries he will get messages which all seem to indicate a lack of appropriate authority to carry out the task.
I have tried adding the domain users name as a user on the PC and making the PC user a member of the PC user's Administrators Group but that did not do the trick.
Any assistance very welcome.

Answer : Network PC user unable to install applications on own PC without being logged in as Administrator

If this is a common issue then use a GPO to add users either to the Local administrators or to the Local Power users group

In the group policy for the OU/Domain then go to Computer Config->Windows Settings->Security Settings->Restricted Groups
Right-click Restriced Groups and select Add Group.
enter "Power Users" then click OK twice.
Under "This group is a member of" - select Add.
Click Browse.
Make sure the Locations is set to the Domain.  
Type in the Group name you want to add eg "Domain users"

All machines in the domain/OU will now have the domain group added to the local Power Users group - AND - any manual group or user that has been added locally to this group will be removed.

Run GPUDATE /force to update the policy