Sounds like this is an example of poor quality workmanship. I say this because it sounds like your line-in is crappy, and the Optical drive sticks and the battery indicator isn't working properly.
Taking it apart (not you (unless you don't care about warranty/are technically super-savvy) - a HP authorized tech) and pushing and wiggling contacts is really what needs to be done.
I recently purchased the dv2000t laptop with the following specs:
-2.0ghz core duo
-geforce go 7200
Ive been having a few problems:
1-The battery life indicator on the bottom left of the screen does not show time remaining, in my old pavilion laptop, it did. any way to fix this?
2-Sometimes when i plug in headphones, the sound still plays on the speaker and the sound in the headphones is fuzzy.
3-Sometimes the cd/dvd drive doesnt respond at all. I have to push it inwards and the light starts flashing, then it works.
Any suggestions on any of these problems, please let me know.