1. PREVENTIVE MAINTENANCE.

That is right preventive maintenance.  Even the computer needs to get a "tune-up" ever so often. This maintenance can be divide into 4 parts.  

1. Backups.

2. Windows clean-ups.

3. Internet Security - anti virus, anti spam, anti torjan, anti worms and firewalls.

4. Remove unwanted programs.

By doing these 4 things as soon as possible, (as soon as you get your computer if possible) and continue the process on a regular basis, even if the worst happens the pain will be minimal.