American Journal of Roentgenology has a good article covering computer ergonomics and Carpal Tunnel Syndrom.  The diagrams show exactly what type of situations you should avoid.

Office Master makes the Discovery DB96 computer chair that I use.  It has a unique pear shaped back shape that forces me to sit correctly.  It is also fully adjustable.  Check it out at your local store.

Office Ergo has some tips for selecting computer seating. Key elements to look for in a new chair:

1) Adjustable Seat Height

2) Seat depth Adjustability

3) Backrest height and angle Adjustability

4) Chair Recline

5) Seat pan angle Adjustability

6) Lumbar support and Adjustability

I have had problems with arm rests in the past.  Typing with arms on an arm rest lead to problems.  I ditched my arms.

You may need to goto a computer chair or ergonomics speciality store and not an office product super store to find your optimal chair.  Try a chair before you buy.

Sit to Stand workstations are starting to become more mainstream. I use one from Workrite.

These allow you to vary your work position to give your back a rest. As they put it: “Ergonomists agree that microbreaks are an excellent way to reduce the affects of repetitive activities. Rather than squirming in your seat late in the day, give your back a rest by standing for a short time. Alternating between standing and seated positions reduces the need for extended workbreaks, increasing employee productivity.”

I try to switch positions every hour or two.

Credit: UCLA Ergonomics
Ergonomics is one of the first things users address when confronted with a RSI. It is really important to setup your computer workstation properly.

Here are some site with good information. PRINT OUT the information you need. Don’t use your computer more than necessary
Office-Ergo.com

Cornell ergo Tips

Humanics-es – Rethinking work ergonomics

UCLA Ergonomics

The most important aspects are:

Remember that just setting up your workstation correctly will not result in instant healing. You have been injured and will need time to heal.