Hi Alan917,
Do you remember making any changes to the computer which the issue started?
How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7
http://support.microsoft.com/kb/929135
Note: follow step 7 to place the computer back to it's usual way
After clean boot if we still face the problem follow the next step as mentioned below and check if the issue is fixed
a) Click Start, type dcomcnfg in the Search bar, and hit enter.
b) In Component Services, double-click Component Services, and then double-click Computers.
c) Right-click My Computer and then click Properties.
d) Click the COM Security tab.
e) In the Launch and Activation Permissions area, click Edit Default.
f) Click Add, type Network Service, and then click OK.
g) While Network Service is selected, click to select the Allow check boxes for the following items:
h) Local Launch
i) Remote Launch
j) Local Activation
k) Remote Activation
l) Click OK two times.
Hope this information helped!
Regards,
Syed Karim