Inspiron 1545 Not Recognizing 60W AC Adapter But Does Recognize 90W

My Inspiron 1545 laptop will not recognize my 65W AC Adapter to charge my battery. I can plug it in and I am able to use my laptop, but it will not charge the battery. I had this problem a year ago. It starts off by telling me that I need to replace my battery. Then after a few days of that, the message saying that it does not recognize my adapter pops up along with it. I am able to use my boyfriend’s 90W adapter for his 6 year old dell though. The 90W has a round jack unlike the shaped jack on the 60W. It is much heavier and I don’t understand how I am able to use a higher Watt. A year ago when I had this problem I spent 2 hours on the phone, downloaded Dell BIOS, and they finally sent me a box to send my laptop back along with the adapter. I don’t know what all was done, but I haven’t had the problem again till a week ago. I’m in college and I love Dell products, but it’s kind of hard to use my laptop when I have to worry about finding an outlet to sit next to because I can’t charge it. I have had my laptop for 3 years now so my warranty is up and I don’t have the money for a $130 - $150 battery or the $60-$70 for a new adapter. Is there any way I can figure out what is wrong or fix it??? I have read some posts, and I have already gotten the BIOS update and even wiggling my adapter around doesn’t work. And I’m pretty sure it’s not my computer or battery since this happened before and they gave me a new adapter. Any help would be appreciated.