How much money would it cost to have this fixed? Is it worth it?

The fan needed cleaning, and so I took it apart to clean it, and it really did need cleaning, but I eventually got it. The only problem is that now it won’t turn on at all. I must have put something back in wrong, but I don’t know what. The battery light won’t turn on, the laptop won’t turn on, and it won’t do anything at all. It’s not the biggest deal if it’s broken for good, but I do like it, and it’s my secondary computer. My question is weather this is something easy to fix (if someone knows what it most likely is), or how much it would cost to have it checked out and possibly repaired. Would that be worth the time and effort? Or should I just replace it?