Malicious URL BLOCKED c:\Windows\system32\svchost.exe

Malicious URL Blocked message keeps on popping up. Ran full scan removed 2 viruses but problem continues; computer shuts down and reboots often. please help.

follow this guide and attach the logsā€¦not copy and paste
http://forum.avast.com/index.php?topic=53253.0

AdwCleaner
Malwarebytes
OTL
aswMBR