Weekly

• Defrag. 
• Clear internet cache.
• Virus scan.
• Spyware/Malware scan.
• Incremental backup
• Outlook/Thunderbird backup.

Monthly

• Full backup.
• Remove unused software.
• Check/Update system drivers.
• Check load temps.
• Clean fans/filters.
• Check hard drive(s).

Bi-Annually/Annually

• Check filters.
• Check coolant (water-cooling).
• Update software.
• Update bios.
• Check wiring.