Security Center Service Will Not Start

I have been installing, using and unistalling several anti spyware, anti
malware and anti virus programmes one after another in a vain attempt to get
rid of "em.pc-on-internet.com" pop-unders on my standalone PC running on
Vista Home Premium.

I finally managed to stop the pop-unders (at least for the moment) by
downloading and running a programme called ComboFix. I also followed it's
suggestion to delete all prior Restore Points.

Unfortunately, now the Security Center Service does not run on start up,
although Defender and Firewall seem to be working OK, as does the installed
anti virus (NOD 32 by ESET). At least I don't keep getting the annoying "User
Access Control Is Turned Off" messages that usually plague me.

When I try to restart the Security Centre in Start/Programmes/Adminstrative
Tools/Services I get the error message:
"Error 1079: The account specified for this service is different from the
account specified for other services running in the same process"

Any ideas on how I can restart the Security Centre.
I have no old restore points to fall back upon, and I do not wish to have to
re-install Vista, as I only have the OEM installed copy (ie no discs) and
would lose all current work & configurations.

Thanks in advance.

Ian

Edit:
As a further bit of information, if I right click "Properties" for Security
Center whilst in Services, I get the error:
"Configuration Manager. The specified device instance handle does not
correspond to a present device".

"ianc1505" wrote:

> I have been installing, using and unistalling several anti spyware, anti
> malware and anti virus programmes one after another in a vain attempt to get
> rid of "em.pc-on-internet.com" pop-unders on my standalone PC running on
> Vista Home Premium.
>
> I finally managed to stop the pop-unders (at least for the moment) by
> downloading and running a programme called ComboFix. I also followed it's
> suggestion to delete all prior Restore Points.
>
> Unfortunately, now the Security Center Service does not run on start up,
> although Defender and Firewall seem to be working OK, as does the installed
> anti virus (NOD 32 by ESET). At least I don't keep getting the annoying "User
> Access Control Is Turned Off" messages that usually plague me.
>
> When I try to restart the Security Centre in Start/Programmes/Adminstrative
> Tools/Services I get the error message:
> "Error 1079: The account specified for this service is different from the
> account specified for other services running in the same process"
>
> Any ideas on how I can restart the Security Centre.
> I have no old restore points to fall back upon, and I do not wish to have to
> re-install Vista, as I only have the OEM installed copy (ie no discs) and
> would lose all current work & configurations.
>
> Thanks in advance.
>
> Ian