initially my battery pack would not charge so i changed that. Are you saying you changed the battery or changed the power adaptor?
Do you use your laptop while it is plugged in to the mains charger a lot? This can be a sure fire way of killing your battery.
If it doesn't charge then it's the battery. If it does charge the charging circuit in your laptop may be damaged. There is usually a specific diode that blows (Happens a lot in digital cameras too) which will stop the battery charging fully.