Excise consultant

We are small computer company doing various activities like   trading of computer components, Servicing (Maintenance), Rental, assembly , upgradtion of ready computers etc.  In previous year FY 2011-12 our total turnover crossed 4 Crores but the manufacturing activity (assembly of computerts) was only around 65 Lakhs.

We want to know whether our activity falls under excise and should we do registration under excise.

Any consultant who can guide us can also contact me.

Ravi