Windows XP was harder to maintain than Windows Vista or 7. My process was as follows:
- Windows Updates
- Hardware driver updates
- Application Updates (microsoft office, browser plugins, etc.)
- Data abstraction / organization and Backup (keep my saved data, such as documents, photos, etc. stored in a separate folder which I could quickly back up)
- Malware protection updates & maintenance, including antivirus and software firewall
- Annual Overhaul (see below)
I also did an annual 'Overhaul'. Once per year, I would do the following:
- Backup all data
- Wipe hard drive by doing a Zero-fill, and reformat.
- Perform any hardware updates and upgrades if I needed them. Examples included: BIOS updates, RAM upgrades, hard drive upgrades, and video upgrades.
- Hardware cleaning -- a lot of dust can build up in the system over 1 year, so getting a 30psi or greater air compressor and blowing the thing out will help to keep it cool and quiet, and extend the life of your components.
- Reinstall Windows XP fresh, and get all latest drivers and updates
- Install only applications I would use (I was always surprised by how much I had installed after a year, yet how little I actually used)
When Windows Vista came out, I have actually changed my process somewhat. First, I actually don't use third-party antivirus or firewall software anymore. I'm pretty careful about what I download and what websites I visit, and for over 2 years, I've been virus free :) Obviously this isn't ideal for everyone -- especially anyone who has a PC used by more than one person, or somebody with kids.
Second, Vista seems to do a MUCH better job of maintaining its performance levels compared to Windows XP, which would get slow over time. I will do a defrag from time-to-time, but beyond that, Vista doesn't seem to need the reinstall like XP did.
Hope this helps!