rpcss vanished from Registry

Hi.
The Remote procedure call service is no more.
Os: XP Sp1
A scan with Avast Antivirus detected this :
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3/6/2008 23:56:19 Luiz Márcio 1280 Sign of "Win32:Rootkit-gen [Rtk]" has been found in "C:\WINDOWS\SYSTEM32\SVCHOST.EXE" file.
4/6/2008 00:42:03 SYSTEM 1676 Sign of "Win32:Rootkit-gen [Rtk]" has been found in "C:\WINDOWS\SYSTEM32\SVCHOST.EXE" file.
4/6/2008 00:42:27 SYSTEM 1676 Sign of "Win32:Rootkit-gen [Rtk]" has been found in "C:\WINDOWS\SYSTEM32\DLLCACHE\svchost.exe" file.
4/6/2008 00:42:47 SYSTEM 1676 Sign of "Win32:Rootkit-gen [Rtk]" has been found in "C:\windows\system32\SET23.tmp" file.
4/6/2008 03:23:38 Luiz Márcio 2412 Sign of "Win32:Rootkit-gen [Rtk]" has been found in "C:\I386\SVCHOST.EXE" file.
4/6/2008 05:38:28 Luiz Márcio 2412 Sign of "Win32:Rootkit-gen [Rtk]" has been found in "C:\WINDOWS\Temp\_avast4_\unp28195895.tmp" file.
4/6/2008 08:26:03 Luiz Márcio 2412 Sign of "Win32:Rootkit-gen [Rtk]" has been found in "C:\WINDOWS\Temp\_avast4_\trz26.tmp" file.
4/6/2008 08:27:39 Luiz Márcio 2412 Sign of "Win32:Rootkit-gen [Rtk]" has been found in "C:\WINDOWS\Temp\_avast4_\trz27.tmp" file.
4/6/2008 08:28:45 Luiz Márcio 2412 Sign of "Win32:Rootkit-gen [Rtk]" has been found in "C:\WINDOWS\Temp\_avast4_\trz28.tmp" file.
4/6/2008 08:29:26 Luiz Márcio 2412 Sign of "Win32:Rootkit-gen [Rtk]" has been found in "C:\WINDOWS\Temp\_avast4_\trz29.tmp" file.
4/6/2008 08:36:33 Luiz Márcio 2412 Sign of "Win32:Rootkit-gen [Rtk]" has been found in "C:\WINDOWS\Temp\_avast4_\trz2A.tmp" file.
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It put in quarentine these, and extracted de svchost.exe from de directory i386 of the Dell OS reinstalation cd .
Then, after a reboot, no drag and drop , no system restore, not opening of property sheets, the visual of the taskbar changed.
Almost no services running. RPC server not running mensage.
I made a backup of the registry 20 days ago in a .reg file, and another now.
Would it be advisable to try to add what is missing in the registry ?
I've copied all that make reference to rpcss in the old and new registry, and saved in two text files. Attached these 2 here.
I think only the keys
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RpcSs]
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RpcSs\Parameters]
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RpcSs\Security]
should be added. Or maybe this one too:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RpcSs\Enum]

The data under these keys and values can remain the same ?
I really don´t the risks involved in this procedure !!
I attached too what is missing of svchost.

Thanks,
Luiz.