Hi Ram,
In your case your company has not sold the old comps, hence in my opinion, cash / bank account will not come into the picture. Your company has just replaced the old comps for new ones.
I would suggest following accounting entry (along with one example) :-
Suppose, WDV of old 3 comps is Rs. 7,000/- ; purchase price (gross) of 8 new comps is Rs. 40,000/- ; seller agreed to deduct Rs. 6,000/- from selling price on exchange ; hence, company has paid only Rs. 34,000/- (after deducting Rs. 6,000/-)
Now, the entry would be :-
Computer A/c. ........................ Debit 40,000/-
To Computer A/c. (old) 6,000/-
To Bank Account 34,000/-
Now the balance in Old Comp account will be Rs. 1,000/-. Just write off that amount to P&L A/c.
Entry would be :-
P & L A/c. .............................. Debit 1,000/-
To Computer (old) A/c. 1,000/-
ALL THIS IS WHAT I THINK, OTHER VIEWS ARE WELCOME.