I would lean towards it being a screen issue. Unfortunately, you can't know 100% until you try replacing one of them. I would recommend replacing the screen for multiple reasons. Firstly, screens are typically broken by being dropped or another form of physical trauma, which is what happened here. In my experience, backlight fuses typically fail due to liquid damage or power issues. Secondly, replacing the entire lid has less risk. If you pick a good listing for the lid, you have the option to return it and only be out some shipping money, whereas if you replace the backlight fuse needlessly you run the risk of destroying the motherboard. Let me know if you have any questions!
Sounds like either a failing hard drive or a messed up operating system. If you can remove the drive and plug it into another computer with a SATA to USB adapter, you can test it with Crystal Disk Info (a free application). That should tell you if your drive is failing or not. If it tests 100% it should be an operating system issue, which would be solved by reinstalling whichever version of Windows you're running, which can be done with an installation disk (you can create one for free with a functional computer, just google "how to create a Windows boot CD). If any of this is over your head, any local computer repair shop worth their salt should be able to diagnose this in a heartbeat! Let us know how it goes or if you have any questions!
Very interesting. If you have a SATA to USB adapter, attempting to boot it with your drive plugged in with that instead of internally could remove the hard drive cable as a suspect. If it boots normally the cable is the issue, if it has the same behavior the drive is at fault. If you have another drive you can install OS X on I would recommend trying to boot it from there via both the SATA to USB adapter and internally, to see if it behaves differently in either. The idea here is remove different factors and see which ones removal results in the computer behaving normally, therefore showing you which is the defective part! (if you don't have a SATA to USB adapter you can order one from Amazon for just a couple dollars. Also if you have access to another functional Mac that uses a 2.5" drive, it should be possible to swap the drives around to see if the functional one will boot inside your broken computer, and vice versa) Let us know how it goes or if you have any questions!
My first guess would be the speakers are defective. Speakers are cheap, so even if the issue is something else, ordering unnecessary replacement speakers would not be the end of the world! I can't give you a recommendation on a replacement unless I'm 100% positive on your computers information, but if you enter your serial number into the site below it will give you all the information you could need. iFixit doesn't sell 2008 MacBook parts, but you can get them on eBay! Just search "*year* *model number* speakers". Let me know if you have any questions!