I have come across many useful pieces of software so here is a list. Be aware that some of these may be quite technical and I can't take any responsibility for any damage you do to your system by using this software. The software is believed to be genuine and virus free (at the time when listed) but it is strongly recommended that you virus scan any software downloaded from any web site.
Use any well known search engine to find the following...
- Hijack this
- Ubuntu Rescue Remix (Boot disk)
- Crystal disk info (SMART data)
- Nirsoft (password recovery)
- PRTG (Network monitoring)
- Zenoss (Network Monitoring)