I ran the malware scanner Hitman Pro on a Windows Vista computer, and it detected that C:\Windows\system32\rpcss.dll was infected. I uploaded the file to virustotal.com and its analysis said that 28 out of 53 signature databases report it is infected with a trojan/virus, so it is very likely infected.
I did a
sfc /scanfile=c:\Windows\system32\rpcss.dll, and Windows said the file was corrupted and that it repaired the file and that I needed to restart. After Vista booted up, all it showed was a black screen with the mouse pointer. It never made it to the login screen. I could move the mouse pointer around, but nothing else worked. CTRL+ALT+DEL didn't do anything, and I had to do a hard power down and power on to restart the computer.
The same black screen with mouse pointer happened when I tried to boot Vista into Safe Mode. Then I tried booting from the Dell Windows Vista DVD, and I tried the "Startup Repair" option, but it said it couldn't find any problems. Running chkdsk didn't find any problems either. So I used the System Restore option to go back to a restore point from yesterday, and the system was finally able to boot up to the login screen. But the rpcss.dll file is still infected according to virustotal.com.
Any idea how to fix the rpcss.dll file and not run into the black screen problem?