Vista - Security Service and DVD Burning disabled

I'm new to this forum, so please forgive me if I'm not up on all the goings-on. I did a search here to resolve these issues, and the fixes posted didn't seem to work for me.

The machine is an HP Pavilion running Vista Home Premium 32bit.

A few days ago, I noticed some differences, notably the Security Service could not be started. A virus "b.exe" was definitely on the system.

Norton Antivirus and Kapersky found nothing. Windows Defender found 35 problems and fixed them. After that time, I was asked to do a Windows Update where SP2 was installed. (This is not my machine, but someone who doesn't speak English. I'm posting for him.)

After those changes, the "b.exe" virus appeared to be gone, but with it, the ability to burn CDs or DVDs in any program including Nero and Windows. I open Services to change Security Service from Disabled to Automatic, but after a restart, it reverts to Disabled once again.

Another clue I can give you is that on startup, I'm asked to find a program to run something called "H" (no extension), which indicates to me that there's still a virus on the machine.

Please help me find a way to:
1. Burn CDs and DVDs once again
2. Keep Security Service on Automatic on each startup.

Thanks in advance for any insight you can provide.

I would suspect that something is still lurking on the computer.
See what these come up with. Don't be impatient, it could all take quite a bit of time. Reboot after using each one.

Superantispyware. Free version - Complete / full scan.
SUPERAntiSpyware.com | Remove Malware | Remove Spyware - AntiMalware, AntiSpyware, AntiAdware!

Malwarebytes - Free version - Complete / full scan.
Malwarebytes.org

Malicious software removal tool -
Download details: Windows Malicious Software Removal Tool

Let us know how it goes.

I want to thank you for the quick response. The combination of the three programs did give me back the access I was looking for.

However, I'm sure there's some sort of virus lingering on the machine because at startup, I'm asked to choose a program to open a file named "H" (no extension). Its name makes it impossible to do a search. Has anyone seen anything like this before?

Thanks again for your help!

Thanks for responding.
It may now be prudent to scan with
CCleaner - Builds
I would recommend the Slim Version at the bottom.
Hope that helps.