SBS 2008 server running out of space?

Hi Guys,

Our SBS 2008 server's system drive (C drive) is running out of disk space so we need to cleanup some space. Can you guys tell me if it is completely safe to delete the log files located under these directories? 

C:\Program Files (x86)\Microsoft Forefront Protection for Exchange Server\Data\ProgramLogArchive

C:\Program Files (x86)\Microsoft SQL Server\MSSQL.1\MSSQL\LOG

C:\Program Files\Windows Small Business Server\Logs\MonitoringServiceLogs

Also, how about the files inside these folders? Please advise.

C:\Windows\winsxs

C:\Windows\Installer

Thank You very much!

Arnel